I've recently moved into a new house, and one of my new roommates has a cat. I like the cat, but every tiny thing he does drives me crazy. When he drinks out of my water glass or hops on the counter to get to the window sill, I can't take it. I don't want him knocking stuff over and getting his dirty cat paws all over the place I prepare my food. Since I'm home alone with him often, I think it behooves me (I'm behoven?) to keep him in line.
Contrast that to my sister's cat. I've known her for four years. Also, much of that time I didn't actually live with her and was never responsible for her in any way. Because of that, if she's on the counter when I come over, I don't think that's gross; I think, "Wow, she looks very regal up there." If I was a good person, I would help train her, too, but we already know that I am not.
The same goes for my city. Being from Duluth, I am allowed to rag on its weather, lack of activities in the winter, job market, etc. However, if an outsider starts bagging on my city, I want to tell them to, "Ride your polo horse back to your gilded mansion with your pool filled with caviar and jet skis and never come back! Dick!" Why? Because they don't also appreciate how awesome Duluth really is.
Friendship works in a similar way. When I go out with my buddies and one of us (oftentimes, me) gets out of line, we largely let it slide and it is completely forgotten the next day. One time at the U, a couple buddies told me I could go pleasure myself, left me at a party and locked me out of my own dorm room after the girl I was making out with tried to punch them for some reason. All we could do was laugh about it the next day. On the other hand, if a stranger looks at one of us the wrong way, we want to fight them. We generally don't because we don't want to get arrested or get our faces caved in, but still.
The point is, loyalty matters. In a perfect world, things would probably even out a bit between the ones we know and the ones we don't but...oh, my sister's cat is standing up on her hind legs like a ferret! She is HILARIOUS!!!