The idea that you have to be funny to be in improv is absurd and one of the most misunderstood aspects of improv.
You don’t have to be funny… in fact it is best if you aren’t funny, or at least don’t try to be funny.
Why don’t you want to be funny…
The joke is one of the most abhorred things in improv, it is cheap, easy and often used at the expense of other performers and at the cost of the scene.
A joke is most often a anecdote that is unrelated to the scene that pulls focus from what the scene is actually about.
Avoid the joke by staying in the reality of the scene and following the principles of improv, agreement, listening, character and emotion.