This ties in a little bit with what Zhavric is talking about, and is sort of my ultimate "one that got away" story, but is mostly just kind of an abstract thing. Confusing, I know.
I'm in my mid-40s right now. In 4th grade I went to a new school that just opened up, so all of us were new to it. The very first day I saw this girl and had an immediate crush on her. As long as I knew her, I was as close to in love with her as a kid that age could get. Even if I dated other girls, I always wished it were her...but we never dated and I'm still not sure why. I think she had friend-zoned me even way back then. She was in my class or at my school up through freshman year of high school, when my parents moved us a whole hour away, which seemed like an insurmountable distance at that age, and without all the electronic communication we have now it was pretty much the last time I figured I'd see any of my old friends.
And for 30 years, it was, until I found one of them on Facebook about a month ago, and eventually found the one I had the crush on. I got back in touch with her, and of course she's married with kids, but she's absolutely gorgeous still (an accomplishment at our age), and *seems* like the same awesome chick I grew up with. So, the regret that I didn't perhaps try to stay in touch with her, find her after high school, etc. has loomed large these past few weeks...but as already pointed out, I don't really know her. A lot happens to people in 30 years, so even though she seems great, she might have all kinds of issues that would have been deal-breakers for me. Assuming of course she didn't find the same with me.
In other words, while she might always be the "one that got away" for me, the chances of it working out even if I had stayed and we dated are almost nil, and even if she were single now I might realize she's not anything like the girl I once knew. I'm "missing" a fantasy that more than likely isn't true. I'm building her up in my mind as the perfect woman, and she isn't.
All that being said, dammit I wish she were single so at least I could try!