I don't think anyone really knows why. There are many things involved in it and they vary from case to case and from person to person; even from one period in time to another. There are just too many possibilities and variables and combinations of those even to know.
Crushes are merely a way for the body to tell us we need to "mate", and yes, even those who couldn't reproduce with their partners (ex. homosexuals) or those who don't feel the need to "reproduce" (ex. asexuals) usually have at least a romantic desire to be with another human since this is a pretty basic human function for most people and it's extremely rare that the chemicals in our brain will not form this behavior called "crushing". Personally, I think that, if you convince yourself that crushing isn't a big deal and find ways to deal with the small sparks of emotion that rise, you can usually "overcome" any crush, even if you're like me and the chemicals never quite stop making more of themselves... Still, usually it's fine and perhaps more healthy to remain optimistic and reveal your crush to somebody. I guess I don't see myself as deserving or a safe person to be in a relationship, despite being emotionally, physically, and probably as sexually mature as a virgin can get. Now, I know some people are more mature than me, but in general I am as mature as I want to be... but this thread isn't about me. XD Crushes can suck, but it's best to remember that you can either choose to embrace them, hide them, or ignore them like me, and there really is no right answer except for what is best for your mental health.
