Mine are like many that have been mentioned:
Spurs 2013 Game 6: I have been a Spurs fan since I was a kid and thus have had a lot of great moments with some heartbreaks in between. .4, 2006 series vs. Mavericks, 2011 series with Memphis were tough, but don’t compare to having the title in your hand and snatched away, as someone said. I couldn’t sleep that night and knew the series was over even with a Game 7. 2014 brought redemption, but I still can’t watch Allen’s shot and dread the highlight each Finals season.
Longhorns 2008 loss to Tech, Colt’s injury in the MNC for obvious reasons. You all noted that 2010 was a continuous gut-punch and really showed the program’s deterioration. 2016 loss to Kansas, while bringing Strong’s much-needed firing, was devastating especially since it was just so embarrassing.
I must admit I am glad I was too young to see or understand the 1984 Georgia loss. As I grew in my Longhorn fandom, just hearing the story became upsetting. I don’t know how I would have handled living through it.