This came to mind to me many times, but never shared what I thought about it with anyone. In terms of morals and principles I'd say I'm part of a few who still have them when I look around myself. I never cheated on my girlfriend (now ex, but still friends); my friends do with many of theirs. I need to feel something for a girl before things advance, my friends fuck around a lot (guy friends and girl friends) A while back my friend's girlfriend made a pass at me but I just ignored it (she got too close if you know what I mean), I actually lost a friend when one of my friends girlfriends cheated on my friend with his best friend for a month.
I like to think manga and anime helped give my sense morals and principles. If you think about it a lot of anime and manga have to do with love and friendship and doing what is right. In Dragon Ball (I watched since I was kid) Goku never enjoyed killing and left it as a last resort, he'd always go the extra yard for his friends, and stayed with one girl, his wife. I don't want to go too long so I'll just leave it at that (just had college finals). Make of this what you shall.
I prefer not to rely on made-up stories for real world morals. Yes, there are some anime/manga that has stuff that can be applied to real life, but i do not rely on entertainment to shape the way i am