well, my moments aren't embarassing, just devastating :(
1. At this summer program i went to some retarded counselor created designated "Game Boy time" and we couldn't use our GB any other time. (At this time, everyone was playing Pokemon Gold and Silver and it was a big craze) on my Red version I had just beaten the elite 4 and the credits were rolling. Then gameboy time ended. some loser fat kid came up to me and said "Game boy time is over!" and TURNED MY GAMEBOY OFF. I lost my progress in the pokemon league.
2. On yellow, instead of doing the sensible thing and levelling up all my pokemon evenly, I got so frustrated that my Pikachu couldn't inflict damage on brock that i started training a Rattata that I had caught at lvl 2 or watever. That Rattata became my main pokemon so I ended up with a bunch of weak pokemon around lvl 2-22 and a lvl 81 raticate when i challenged the elite 4. I couldn't beat them until I had traded a lv100 Mew I had sharked on my Gold version to Yellow. Then it got stolen...
3. My gold version had a pokedex of 213 owned (mostly due to the cloning cheat that involves the PC, i cloned a pokemon holding a masterball) then someone stole it.
4. buying sapphire version instead of Ruby. ;)
5. This isn't really embarassing, but today I just went to the Pokemon Event happening in my town, and I got Raikou and Typhlosion for my firered and Dragonite and Latios for my leaf green, and Celebi for both, but then my mom took away my GBA SP charger, said I was grounded.