For reasons that I can't explain, the two things my cats will not tolerate are a closed door, or an empty litter box.
I don't know how or why it happened, but long ago they decided that they did not like the sight of a clean litter box. Not just that, but one always wants to be the first to break the seal after a fresh cleaning.
Occasionally I have found him standing in the box, grunting, trying to push something out even though he didn't have to go, just so he could be first.
But today I watched him fail while trying. He left, came back a short time later and tried again. Again he failed and left, so I followed.
He went to the food bowl, ate, drank, walked a few laps, then returned to the litter box.
This time he successfully pinched one off.
The smug look was priceless. Like somebody that had just figured out how to beat the system.
A hero in his own mind.
I can't train him to not step on my balls while I sleep, but he can figure out how his digestive system works?
It's all about motivation, and the cat cares more about the litter box than me, I guess.
One of my cats is somewhat similar. Probably 75% of the time I go to clean the litter box, he jumps in it before I can even finish cleaning it and either pinches one out or lets the garden hose flow. I've never seen him fail at it; he always has something saved up for when I clean it.