I haven't beaten the first one yet, but Kay didn't really annoy me. The thing that bugged me was "little thief." That just killed my suspicion of disbelief.
"Little Thief" didn't really bother me much. It's basically a computer model/simulation tool that they made casual for the user to interact with. In fact, another angle they could have used is to have the Kay be a sort of sketch artist and simply draw out the scene, but it's clear the designer wanted a way for the user to be able to continue to investigate with the normal interface.
The devices is also ridiculously easy to program. :-p
I do seem to recall a lot of the jokes revolving around the device were pretty stale.