“What’s funny is that our cat-sitter is Russian.”
Yes. That is funny. It would take a scientist several months to work out exactly why and how it is funny, but the important thing here is that you are absolutely right about the comedy value of a Russian cat-sitter. First of all, you have a regular cat-sitter. Second of all, the fact that they are Russian is a seemingly unimportant detail that you felt it necessary to state. Third, the fact that yout hink it’s funny for some reason is, in and of itself, rather funny.