Weak jokes

I wondered if many of you often experience that excruciating moment when a rather lame joke falls flat.

Some years ago I had a car fitted with a Blaupunkt radio. At the time they were naming their radios after cities so there was a Paris, a Madrid etc. Mine was a Casablanca. When it broke down I took it to be mended and a couple of weeks later picked it up again. As I left I said to the man who served me
“I knew I would regret buying it. Oh, maybe not today, maybe not tomorrow but one day and for the rest of my life”
“Oh no” he replied “Usually they're quite good”

This came back to mind when, quite recently, I had to go to the nurse to have blood taken.
“Do you mind if I ask you some questions first” she asked and I replied
“That's OK but I'm not very good on 18th century foreign policy”
“Oh no, they're about your medical history” she said.

It seems to me that here are a few possibilities.
1 They just don't realise that it's a joke (just)
2 They play back deadpan on purpose. If I cottoned on fast enough that might be what I would do.
3 They think 'Can't this annoying old duffer see that I'm busy?'

I suppose I should stop but I know I won't. Anyone else equally annoying?