For me, a joke is in most cases a reaction to some situation. I have trouble telling jokes on purpose.
Jokes come to my mind when I am in a conversation. I like funny word play. Sometimes a situation makes me remember a joke, sometimes then follows a chain of several jokes ("Oh, I remember another one. Wanna hear? Well, it goes like this....").
I like watching the old interviews with Robin Williams on Youtube. They are fireworks of jokes, triggered by the questions of the interviewer. I am maybe 10% of that...