This is one of my favourite discussion topic.
In your opinion and experience, which of the following factors make it the more difficult for two individuals (e.g. a couple) to understand each other or live together ?
1) Gender : the Mars and Venus polarisation; add to this the gays and bisexuals, and things get even more complicated.
2) Intelligence and knowledge : intelligence is mostly innate, while knowledge is entirely acquired, through education, self-learning and experiences.
3) Religion and (metaphysical) beliefs : a radical Muslim will have a hard time living with a convinced Atheist (and vice versa). Christians of different denomination (e.g. Catholic vs Baptist) and different strength of beliefs will also probably be in an antagonistic position.
4) Social class : values, tastes, manners, lifestyle, living standards...
Let's say that personality is defined by the combination of all the above, so please do not answer "personality".
My views :
In my experience, gender has been the least dividing of the 4 factors. Maybe that is because I belong to minority groups in the other three. In fact I have often had a better contact and more interesting discussion with women than with men. I think that (some) women have an appeasing effect on me, which makes it easier to be in their presence. When I get annoyed by women, it is usually for another reason than "gender conflict" - except if rationality is part of the gender division, but I doubt so as their are many rational women too (at least in some cultures and social groups).
Intelligence and knowledge is often the cause of conflict between me and others, so I try to socialise with people similar to me, or avoid "serious discussions" with people who have had too difficult to understand me in the past. Let's say that I have more or less managed to cope with this difference. For most people (the "mainstream", as I see it) it isn't even an issue.
Social classes are part and parcel of any civilised and specialised society. Only animals and tribal people (or our prehistoric ancestors) do not have to care about interpersonal differences in knowledge/education and social class. Let me emphasise the difference between "social class" and "social status". One's social status depends on one"s achievements or personal dominance over the others, and exists also among social animals (e.g. wolves, apes) and tribal people. Social class is the milieu into which we are born and raised, and which will influence our values, tastes, manners and lifestyle during all our life, whatever our socio-economic success.
Personally I think that social class is a much more important factor in the way people socialise than gender, intelligence or knowledge.
Religion wouldn't be a problem if nobody had one,
which contrarily to the other 3 factors is possible. It also wouldn't matter so much if all religions were non-exclusive polytheisms. For instance, Buddhism and Jainism were absorbed by Hinduism. The Romans absorbed the deities of the conquered lands (e.g. the Egyptian and Celtic ones). Religion started to divide people when they became exclusive and intolerant of other beliefs. This is only true of a few religions, Judaism, Christianity and Islam, that have since "killed" most of the other religions in the world, and continue to do all they can to dominate the world. Naturally two radical individuals from two such religions will never be able to live together. It is as hard for one radical monotheist to live with a polytheist or a non religious person (even from the same religious background !)
So for me, religion is by far the most dividing factor. Were I not already married, I would never ever consider dating someone with strong and exclusive religious beliefs. I am a convinced Atheist, but I do not look for other convinced Atheists. I am comfortable with most Agnostics (e.g. non-practising Christians who have doubts about religion), Deists (those who believe in god, even strongly, but do not follow any organised religion), or with non radical Hindus, Buddhists, Shintoists, etc. In a secular society where most people are not very religious (e.g. Europe, China, Japan), religion is hardly an issue. But I couldn't live (even for a short time) in a very religious society (e.g. Saudi Arabia, Iran, some US states...).
Conclusion : Within a non-religious society, the most dividing factor between people, and the most important in finding friends or a spouse is definitely social class. But religion remains potentially the most prohibiting factor of all. So my ranking from the most to the least is :
- religion
- social class
- intelligence & knowledge
- gender
Additional comment on gender differences & divorce
Hopefully gender is not such a strong factor, otherwise men and women wouldn't live together anymore. I believe that a majority of divorces nowadays are not caused by gender differences, but by passionate love marriages where "love" dies after a few years (for biochemical reasons), or just marriages across social classes, which are usually destined to fail. The increase in divorces has resulted from major changes in society :
1) allowing love marriages, regardless of the spouse's family background
2) a rise in individualism; young people don't mind to live by themselves anymore, and even want to leave the parental home as soon as possible, but also have more difficulty living with someone else, whoever it is.
3) a rise in the level of what is considered "acceptable" promiscuity (buffered by AIDS since the early 1980's)
4) decrease in the social and/or religious taboo about divorce
Gender differences have always existed. Men and women have lived together for centuries despite these differences. Now that women are increasingly behaving like men (taking men's jobs, doing men's sports, talking like men, cutting their hair...), and vice-versa (men doing more housework, taking care of the children, taking paternal leave when a baby is born, wearing perfume and caring about fashion...), we could think that in fact gender differences are decreasing, and fast !

In your opinion and experience, which of the following factors make it the more difficult for two individuals (e.g. a couple) to understand each other or live together ?
1) Gender : the Mars and Venus polarisation; add to this the gays and bisexuals, and things get even more complicated.
2) Intelligence and knowledge : intelligence is mostly innate, while knowledge is entirely acquired, through education, self-learning and experiences.
3) Religion and (metaphysical) beliefs : a radical Muslim will have a hard time living with a convinced Atheist (and vice versa). Christians of different denomination (e.g. Catholic vs Baptist) and different strength of beliefs will also probably be in an antagonistic position.
4) Social class : values, tastes, manners, lifestyle, living standards...
Let's say that personality is defined by the combination of all the above, so please do not answer "personality".
My views :
In my experience, gender has been the least dividing of the 4 factors. Maybe that is because I belong to minority groups in the other three. In fact I have often had a better contact and more interesting discussion with women than with men. I think that (some) women have an appeasing effect on me, which makes it easier to be in their presence. When I get annoyed by women, it is usually for another reason than "gender conflict" - except if rationality is part of the gender division, but I doubt so as their are many rational women too (at least in some cultures and social groups).
Intelligence and knowledge is often the cause of conflict between me and others, so I try to socialise with people similar to me, or avoid "serious discussions" with people who have had too difficult to understand me in the past. Let's say that I have more or less managed to cope with this difference. For most people (the "mainstream", as I see it) it isn't even an issue.
Social classes are part and parcel of any civilised and specialised society. Only animals and tribal people (or our prehistoric ancestors) do not have to care about interpersonal differences in knowledge/education and social class. Let me emphasise the difference between "social class" and "social status". One's social status depends on one"s achievements or personal dominance over the others, and exists also among social animals (e.g. wolves, apes) and tribal people. Social class is the milieu into which we are born and raised, and which will influence our values, tastes, manners and lifestyle during all our life, whatever our socio-economic success.
Personally I think that social class is a much more important factor in the way people socialise than gender, intelligence or knowledge.
Religion wouldn't be a problem if nobody had one,

So for me, religion is by far the most dividing factor. Were I not already married, I would never ever consider dating someone with strong and exclusive religious beliefs. I am a convinced Atheist, but I do not look for other convinced Atheists. I am comfortable with most Agnostics (e.g. non-practising Christians who have doubts about religion), Deists (those who believe in god, even strongly, but do not follow any organised religion), or with non radical Hindus, Buddhists, Shintoists, etc. In a secular society where most people are not very religious (e.g. Europe, China, Japan), religion is hardly an issue. But I couldn't live (even for a short time) in a very religious society (e.g. Saudi Arabia, Iran, some US states...).
Conclusion : Within a non-religious society, the most dividing factor between people, and the most important in finding friends or a spouse is definitely social class. But religion remains potentially the most prohibiting factor of all. So my ranking from the most to the least is :
- religion
- social class
- intelligence & knowledge
- gender
Additional comment on gender differences & divorce
Hopefully gender is not such a strong factor, otherwise men and women wouldn't live together anymore. I believe that a majority of divorces nowadays are not caused by gender differences, but by passionate love marriages where "love" dies after a few years (for biochemical reasons), or just marriages across social classes, which are usually destined to fail. The increase in divorces has resulted from major changes in society :
1) allowing love marriages, regardless of the spouse's family background
2) a rise in individualism; young people don't mind to live by themselves anymore, and even want to leave the parental home as soon as possible, but also have more difficulty living with someone else, whoever it is.
3) a rise in the level of what is considered "acceptable" promiscuity (buffered by AIDS since the early 1980's)
4) decrease in the social and/or religious taboo about divorce
Gender differences have always existed. Men and women have lived together for centuries despite these differences. Now that women are increasingly behaving like men (taking men's jobs, doing men's sports, talking like men, cutting their hair...), and vice-versa (men doing more housework, taking care of the children, taking paternal leave when a baby is born, wearing perfume and caring about fashion...), we could think that in fact gender differences are decreasing, and fast !