What do you if hear a slightly funny joke?

Acknowledge the humor. Even if the joke is not particularly funny, it is still polite to acknowledge the humor and engage with the person who told it.

Give a small chuckle or smile. This shows that you appreciate the effort and shows you are still listening.

Add a positive reinforcing statement. You can express your positive regard by agreeing with the humor, or finding a nice follow-up joke or playful statement.

Be genuine. Be yourself and let your natural responses come through. It is okay if you do not find the joke particularly funny, as long as you show appreciation and kindness.