Story time.
This took place around Christmas 2011. I was at a friend's Christmas party at their house. A mutual friend, who none of us see too often, arrived with a very attractive girl. Because we were all a few years younger, we partied a bit harder and drank a bit more.
As the night went on, I had been chatting up the attractive young lady who arrived with my friend. She was really cool. Tattoos, worked in the music industry, enjoyed waxing philosophical. She hadn't been drinking that night since she was driving, unlike myself who was in a rather drunken state.
Because of my increased intoxication, I totally blanked when she left and I didn't ask for her number. Realizing this upon my return home, I tracked her down on facebook and shot her a message about how I enjoyed spending the evening with her and I'd really like to see her again.
Well, unbeknownst to me, she had been dating the guy she showed up with for a few weeks, as she indicated in her reply to my message. At no point did anyone think to mention this earlier in the night. What the fuck.
They're still together, years later, and I always think of this whenever I see them. Thankfully, it's still pretty infrequently that we actually hang out.