Do you think I'm stupid? Or is it a girl thing?

This is the case:

No matter how it goes, I will still be more than willing to help someone and go the extra limit if I once had a crush on them. No matter how tiny the crush might be, no matter whether i lasted for 1 day or 1 month, somehow, I just don't mind. The good thing is, they do not know (thus can't really take advantage of me) but.... I wonder why? I would just be ever-ready to do almost anything if I am asked to. Why? Cos I liked the guy before? Cos I thought it would be a nice thing to do? Cos I think that by doing so, he will eventually like me? No... can't be that reason. Cos I'm over him already and.... there is no more crush. But I still treat him so nicely and will do almost anything for him. Why? I still don't get it. Hmmm.... Puzzles me actually. (Kinda thought about it recently so thought I'd blog about it) Anyone experience the same thing? Sigh...