I've been on both sides of this picture more than once.
The first I recall was in the summer before 9th grade, I went to a summer art program for the last year before I would be deemed to old, after having gone every summer for several years. The previous year I made friends with a boy there, and by that year I had grown feelings for him. In short, I was rejected, and he even changed into a completely different person.
Then late in high school, my friend at Tech told me of his feelings, and though I didn't really feel the same, the pressure of the fact that he told me and that my mom was encouraging me to date him made me go ahead. Bad idea. It lasted only a month or so, and the friendship crumbled too.
Last year, in mid-July, I made a friend in one of my classes, and she introduced me to her then-apartment-mates. One of them I fell in love with very fast, and it seemed he liked me as well in the beginning, but by that October/November it was pretty clear he really didn't, if only because he turned into a shallow prick (or perhaps he was one to begin with, who knows).
Right now, I'm currently playing both roles at once. A friend of mine has feelings for me, and I don't for him, and I have feelings for someone I met in a class this past January (whom I often talk about), who doesn't feel the same for me.
The world of love is a madhouse, that's for sure.