I think people with OCD on balance tend to become a lot more emotionally invested in other people's lives than other people. I can't say why, exactly, though it makes sense when you consider how sensitive we are to the world around us.

You have to be careful with this sort of thing, though. People can take advantage of you, whether it is intentional or not. Emotionally needy people can be pretty cruel and you have to keep your guard up so you don't get hurt. Also, if someone does take advantage of you, remember that it's not your fault and put this person out of your mind, pronto.

On the other hand, I think caring about other people is generally a good thing, and you can really be a good friend to the right person. The only thing to remember is to put yourself first.