Joe Kelly has an interesting approach to his jokes. He throws a bunch out. Some of them hit, some of them don’t, but he never tries too hard. He lets Bad Dog do its own thing (which includes not recapping after a years long break between issues) and it sort of works.
His characters are more likable than funny. It makes the humor awkward–because the characters are trying to be funny, them being likable makes their underperforming jokes more acceptable. They–and Kelly–get a lot of leeway.
The art, from Diego Greco, has something to do with it. Greco doesn’t push hard for humor, it’s already in every one of his panels. Bad Dog manages to be genial and biting at the same time, all thanks to Greco.
There’s not a lot to the comic except the concept; Kelly and Greco do a lot with what they’ve got.