According to Bulbapedia, Arcanine was originally supposed to be a trio with Articuno and Zapdos, had to do with a wolf of Japanese lore, but they scrapped the idea and added Moltres.
Too lazy to post a link.
Well I guess not nearly as FFFFFFFUUUUUUUUUU-worthy as some of the others on here but still annoying:
I wanted to get a Togekiss for dex entry. So, I gave my Togepi a Soothe Bell and kept fighting things to level it up and raise its happiness. The only attacking move it knew was Metronome, and after a while, out of all the moves it could've used, it used Fling...