Whoopie cushion
no one can be grumpy when one of those is secreted under the cushion on their chair.
( Windy Pig I'm naturally quite suspicious about the moon., Fri 24 Jun 2011, 10:19, archived)

ditto wearing a sombrero

( Two Hats 🎩🎩, Fri 24 Jun 2011, 10:21, archived)