I was just thinking about this recently - I think in regards to your question, it depends on the chemistry between the people. Either one person telling a joke to another, or a comedian on the stage telling sharing jokes and/or anecdotes with a crowd. The jokes themselves matter, but do the teller and listener(s) vibe? And: does the teller believe their own joke is funny?
In my case, there are certain people that I know or meet that I immediately hit it off with, humor wise. We either constantly tell jokes back and forth or rib/riff on each other, but either way we are able to make each other laugh. There is a certain fluidity to it. I usually feel that from someone right away, being more highly sensitive. It’s a joy to find someone whose humor just clicks with your own.
I’m a little more ‘on the edge’ when I’m trying to make people laugh from the stage. Probably because I don’t have as much practice. But I’ve dreamed on and off of doing stand-up!
Sometimes when I’m reading a poem, people will laugh at lines that I never considered to be funny. In the future I may try and push the line further, emphasize it more in readings, edit the poem to compliment the line - realizing just in writing this that getting laughter from poetry is a huge source of joy.
Maybe people who can have a funny bone and not even know it. Or some people’s funny bones are funnier, or closer to the surface, or technicolor, or embedded in their brain.