He just hates stupidity! XD
This gives to the say "Oh, for Pete's sake!" alot more significance.
He saw himself being nice on "The Mickey Mouse Clubhouse?"
This is that US Army WW2 propaganda cartoon...loved it
I think this is when Donald couldn't get a military drill down right XD
He must've read several comments on Youtube.
he stumbled into the trolls
he must have seen all the pony shite on deviant art