I don't think I have just one word that describes me. I think my mood, personality, and attitude changes quite often. I'll chose the one trait that has had the longest staying power in my life:
Sensitive.
I'm always there to help people out when they are feeling down. I'm very considerate of others and their feelings, and can help them through the worst times. However this trait can also be a weakness. Trying to be nice all the time, especially where it isn't valid, will give people the impression that you are a pushover, and given the selflessness of your nature, you usually don't do anything about it, and this gives others the impression that their disrespecting and unappreciative behavior towards you is perfectly acceptable. I've taken a lot of crap from people over the years. But if there's one thing I've learned, it's that being nice isn't always the right thing to do. Bullshit still happens, and you need to be able to deal with that too, even if requires you to be "mean", so you can put the bad in it's place.
I also don't take to kindly to criticism, blame, and other people trying to help me, or tell me what to do.