I bond more with animals that benefit greatest from human dependencies. If I see a somewhat helpless animal, I immediately grow an attachment with it (no I don't sexually abuse it, you sicko!) and feel a need to 'mother' it. Perhaps I have a good heart or perhaps I like to play god.

Many people I know shut out all possible dependencies on other people. A good thing? Possibly but it does stifle the ability to bond (seriously. You, yes you. Get out this thread now!).

I find it very peaceful to look after an animal. As said above, all the issues humans throw around are missing. Instead, there's something pure and untainted about them.

Choosing, I'd go with my best friend without any doubt. As nice as that feeling is, they wouldn't provide the same stimulation or general benefits of a human. I'd certainly rather a pet than be alone though!