Doesn't what you can't understand fall into the category of "personal beliefs." If a young couple believes they should wait to have sex until after they get married, then that's their business and not yours.
I can't understand many things, but I'm beginning to understand that a lot of the stuff I can't understand is none of my business anyway.
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Do whatever is best fot you, and don't care so much what others do, as long as their actions don't affect your well-being. Big part of the problem in today's society is that nobody mind's his or her own business anymore. Our culture has become like a shrinking, African watering hole, where crocodiles and other animals must come together even though they all don't trust or do fear one another.
It's time to return to basics: common sense, common decency, and common courtesy--all important ingredients that have sadly become uncommon.