The phrase "funny part" refers to the specific moment or aspect of a situation, story, or event that is humorous. It is the part that makes people laugh or find amusement. Full definition
The funny or not so funny part about this story is I would not even be aware this happened had he not then pointed it out to me. (katycouplescounseling.com)
I mean there was literally only two funny parts in the trailer! (allgeektome.net)