Why be good?

[c172]

I believe I have morals, to be kind to other and that golden rule, I didn't get that from the bible. I was raised to treat people the way I would like to be treated. I help people when I can, sometimes I help too much, that could be considered bad by some. It is a pretty loaded question with too many directions to sum up, and it changes. I try to do no harm. That is as simple as it gets. Now, why? I don't want to do things that give me negative feelings, guilt, remorse, and anxiety. That is broken down to the most simple explanation. I don't need a book, but you can get all of the same moral stories from Grimm's fairy tales and My Little Pony. No god required.

The question is: How did we get this sense of right and wrong? Evolution doesn't suggest that males should be polite with females...it suggests that the strongest and most aggressive mate when and where they please. That's just "survival of the fittest", isn't it?

So, in light of that, WHY should men be good on their dates with women v. taking what they want simply because they can like our ancestors might have done a few thousand years ago?

Why does it have to just be men being good to women? Why can't the reverse also happen?