I've got a story of a childish coworker.
We got a new assistant manager that everyone, and I mean EVERYONE, hates, customers hate her, staff hate her. She never does any work and then tries to get other staff to do all her jobs in a blind panic at close to closing time.
Now, she hates when people correct her or tell her she is wrong, even if she is. So, Tingles, my newer coworker, and I were working delivery and we had stacked some animal feed to the top of the racking, she didn't like this, told me it was too high, I told her she was wrong it wasn't too high, it's always this high. I leave it at that and we get on with work. About 15 minutes later I get a walkie talkie message from Grandad, my other coworker, asking me if she had said it was too high, so I said yes and then come into the shop and he tells me he just watched her walk past the feed and deliberately push a bag onto the floor to prove a point, when questioned she lied to him, and then he called her out on it and she went bright red.
So, after I was told this I took Tingles with me and walked up to where she was in the office and said "Don't worry Frog, I picked up the feed you pushed on the floor!"
And as I was walking away she looked very flustered.
It's the small wins!