Yes, I agree that it seems plausible to assume that group behaviour is something like a sub-conscious need which we don't need to learn, as our mind rather inherits those traits from the evolutionary past of the mankind.

And there is nothing bad in group behaviour as such. I think it only becomes a problem when we allow it to affect our reasoning and judmenent too much (again, this often happens without a conscious choice, so it isn't always easy to recognize how our reasoning tends to be biased because of our internal need to defend our own group.)

Well, but individuality is a tricky question, as well =) At least in my own life I've ran through this kind of thought patterns: "If there is one group wearing only black clothes with rivets, and another group wearing only blue jeans, and there is some sort of rivalry between these groups, then what should I wear if I'm an individual who doesn't want to associate with these groups? If I avoid wearing jeans and black clothes with rivets, does that still mean that my individual choice of clothing is still defined in relation to what others wear? That I define my identity by being different from others? Or can I just totally ignore the aesthetical preferences and the associated tribal identity badges, if these things don't matter to me personally? If I wear blue jeans simply because I like them as a practical choice, does that mean that others start to treat me as I were a member of the jeans-wearing group, assuming that I share all the rest of their values and traits?"