I have been taking care of dear friends' cats for the last few days. Today they came home and told me that their cat had gotten locked in the bathroom and looked like he had been there for a while.
I feel so stupid for having not noticed! I'm sure I saw him yesterday, but maybe I was mistaken. How could I have not looked for him!
The truth is I didn't look for him because I often don't see the cats while I'm there. I didn't pay attention to crying because one of them will often cry for no reason.
The truth is I did my best, even if it wasn't good enough.
I have apologized and offered to pay for any vet bills, that is all I can do for now. In the future I think I'll refuse to pet sit for them, at least until I'm sure I can give them my full attention.
Hopefully that is enough.