I thought they may have presumed too much knowledge of certain things for people who are not comedians. Like Montreal. A comic understands what it is and its importance, but someone else may not know about it.
I mean, I`ve had bartenders and waiters and waitresses make a comment about a joke of mine, like pointing out some sort of logic error or something that I`ve never even thought about, and they`re right.
I used to write things out beforehand. But sometimes it backfires.
Source: brainyquote.com