Being sick is not funny business, and someone coming in cracking jokes under dire circumstances may find their humor is rejected. There is a time for humor in healthcare, but it must be mindful. What people think is funny can vary wildly. If humor is used, it should be very mild and universal. It's a good policy to be kind, tolerant, professional, and compassionate with your patients. Certainly, laugh at a child's joke, if appropriate, and acknowledge a patient's attempt to be cheerful, but follow rather than lead with humor and only support, chuckle or smile at anything that would be universally accepted as OK. Some people poke fun at themselves, but sometimes, it's a self-esteem issue so it's best to avoid playing along.