For the majority of my life I've had a crush on someone who had no idea I existed or didn't pay me any attention. This 'someone' has not been the same the whole time but in some ways might just as well have been.
I think this feeling of unrequited love is comfortable for me. I know what it is when it hits and I know how to deal with it. Daydreaming about someone who will never have much interaction with me in real life is predictable. It's easy to handle. I'm in control.
It's a feeling that hurts in the same was starving myself for half a day does (I rarely ever do this anymore). It pushes some of the same buttons of high and low feelings.
I used to desperately want someone to love me because I don't really love myself. This is changing though, I'm working on it. I no longer hate myself and sometimes even think I'm pretty alright. But I don't think this need for unrequited love will go away any time soon. It still feels too familiar and I would probably miss it if it went away.
I would like to someday be rid of the need for this longing for a person who doesn't want me, but it seems like one of the most reliable things in my life right now and its familiarity is just so comforting.