Dragon Driver
Fear the Dragons
Wasting my Master Ball on a Donphan on Silver when I was 7. It took me 6 hours to catch Lugia
Cloning my Blaziken so that my friend could use it to help him with the E4, then forgetting which Blaziken was the original
Waisting my masterball on a shiny pokemon
Got tricked in a trade by my 'friend'. I traded my carefully EV'd Rhydon to become a Rypherior, and he took it, ran away, normal tricking. It was dumb, and he never gave it back.
He moved away 3 or 4 days after that.
i regret unnicknaming a pokemon for a trade...i thought it was a clever name!
I lost my HG when I popped the game cart out to replace it with Black... Had loads of rare pokemon, was going to transfer them all, still can't find it. Failure.