That's likely too. In scenarios where we're supposed to have a high expectation, we tend to laugh harder at anything humorous. The show "Silent Library" from Japan is an example I use, where people give each other harmless but painful punishments in a library while others struggle to conceal their laughter. The expectation of silence and scholarship in the library heightens the humor, and the show is very very successful and has spawned multiple spin-offs.

Being drilled that the customer must be respected and is always right would probably create a similar situation when they reveal themselves to have done totally idiotic things.