I don't always make errors of judgement, but when I do, I absolutely, utterly, totally blow it.
So I was playing Pokémon X and caught exactly 8 Eevees. Yeah, I was planning to evolve them. First, I took three of them and gave them the Water, Thunder and Fire Stones. Then I traveled across Kalos searching for the Ice and Moss Rocks. I ended up accidentally leveling up two Eevees in Frost Cavern and Wonder Traded one of the new Glaceons away. The Moss Rock didn't cause much problems... at first.
Then, I had three Eevees, who would become an Espeon, an Umbreon and a Sylveon. My solution was tour Kalos aimlessly until they'd evolve. Then... in retrospect, I'm not sure what in the name of Arceus I was thinking. Only, it was stupid. I ended up leveling up all three Eevees... at Route 20. Right next to the @#€&% Moss Rock. So I had now four Leafeons at once. So, solution: Wonder Trade binge, back to Route 10, catch three new Eevees, back to Square One. Also, hit the wall till your head hurts. I kind of deserved it.
At least I got an Electrike, a Makuhita, and a Magneton out of the deal.