Cat b hated water. Cat a you could put under a shower and he'd be happy.

Cat b hated nail clipping. Well, about three paws might be tolerated but then it'd be enough and you got the teeth. Cat a didn't mind.

Cat b hated trips to the vet. Somehow he knew and would find the strangest hiding places that day and fight all the way into the carrier and out. Cat a would purr and brush against the vet, happy to see new people.

Taking medicine...

It wasn't that cat b wasn't chill or happy to be around people or anything, he was a big softy, really. But I can't think of much that cat a complained about.