When I first started playing Pokémon, at a point I had six members on my team and went on to catch a seventh pokémon that I really wanted. Upon being told it had been transferred to "Someone's PC", I panicked, wondering if I would have to go through the entire region to find this person's PC. Failing to notice how illogical my pokémon being transferred to a randomer's computer would be, I restarted the game. :(
Haven't done it since, as I adore the post-game stuff and would hate to lose everything I've collected.