I've had a few recently, accidentally auto-albumed a few stamps I ABed worth 20m+ each by being lazy about price checking. This wouldn't be so bad if they were at least avatar albums. They weren't. I'd rather have sold them to fund stamps I need to complete other albums.
But the real big regret is being the dumb-ass I am, I decided to spin some wheels without securing my inventory and the Pant Devil stole my Lab Ray stamp at the wheel of misfortune.
Sloppy mistakes.