Just having constant hope shot down repeatedly by the only girl to ever give me butterflies.
If anyone wants to know the story - we met in school & she was & is the only girl I've ever really, really liked. We were always quite close but I wasn't the coolest kid when I met her & I was only 15, I'd always liked her & I think she always knew, I asked her out once when we were like 16 & she said no, I was too shy to talk to her again but she kept texting me and soon enough we were back to being close friends, I still kept hinting for about 2 years but never had the guts to ask her out.
At about 17-18 we started seeing each other a lot more out of school (everyone just kind of said we were dating but it was never how either of us it, even though I wanted us to be, of course) and then one day she messaged me one night after we'd been hanging out saying was interested in me as more than a friend, and that she wanted something more. I handled it really badly, I'd never had such a clear sign she was interested in me & I kind of panicked, I got clingy & wanted her to make some serious decisions as soon as possible but she said she wanted to just calm down & see what happens which just went over my head. We starting drifting after I was such a douche & one day she said couldn't be with me which was the most devastating thing I'd ever heard. By this point I was 18 & had been kind of a late bloomer so I was confident(ish) and decent with girls so as we stopped talking completely I talked to a few more girls for a while and hooked up with a few but it was only ever casual.
After a few months we'd started talking casually again and then when school finished we were all out celebrating our exams finishing and I saw her, we spent a decent part of the night together and she bought me some drinks, got drunk and apologised for "everything". So a week or two later we went out together again and for what felt like the 1000th time we started flirting heavily again, she said I could come spend the night with her when she was at university, etc, etc. and then we both went. We didn't speak for 4 months until Christmas, she asked me if I wanted to go for a drink, we did, it went terribly because we both wanted reasons as to why neither of us made any effort over the past months and we ended up arguing on the way out and I haven't spoken to her in 6 months now after some occasional texts last summer.
She is without a doubt the only girl I've ever had real feelings for, I don't have her number saved anymore because I'll give in & text her, I've been with quite a few girls since we left school (all casually) and not with any of them have I had even an inkling of the feelings I had with her. She's my dream girl no doubt & I like to think a different time and place we would have been luckier.
TL;DR: I hinted, I asked & got rejected. She hinted, I asked & got rejected. Still think about her.