Oh yes, definitely. I think that the two most important personal qualities in real life to me are loyalty and integrity in equal amounts. "My country, right or wrong" or "I'll stand by my man, even if he's a criminal" don't cut it for me. But neither does the idea of ditching someone in favor of self interest. I'm always disturbed when someone professes great loyalty to someone/some some idea or group, and then one day up and dumps it all. I love best the people and/or characters who have integrity and can be loyal despite all kinds of seeming obstacles. (It also ups the unresolved tension in a book, that longing for connection + obstacles.)

And now that you have brought this up and made me think about it, I think I could probably spill a bit of this in both my good characters and my bad ones. :)