I'll poo in your shoes for that...

(this one, obviously, might contain a wee bit of TMI)

This morning, the Mr. noticed both cats confronting each other (wrestling on top of his shoes--the shoes live on the landing) than sitting on the landing at the top of the stairs, glaring at each other, while he was preparing to leave the house.

This is unusual; they usually glare from farther away than that. He was determining what the glaring was all about, (whether El Gato was plotting something devious and La Doof Kitton was 'helping' or whether La Doof Kitton was plotting something devious and El Gato was thwarting it, or of La Doof Kitton was just preventing El Gato from going to the basement to use her litter box--this can be an ongoing problem, not helped by the fact that El Gato has tummy/digestive tract issues) as he reached for his shoes.

Both cats watched him with interest and looked very disappointed that he noticed the bit of cat poo BEFORE he touched it/put his shoes on/stepped in it.

We're not sure which of them did it--El Gato is the one with issues that relate to poo but La Doof Kitton is more likely to pick up a piece of poo and plant it in a shoe. It might have been a joint effort.
Regardless, I'm taking this to mean that they have NOT yet forgiven us for leaving them with a pet sitter and that I should sleep with one eye open and check my shoes before work.