Simpsons-episodes produced the last 13-14 years or so have been remarkably unfunny. The only reason I sometimes watch some of them is to see if they continue to be unfunny. And that has always been confirmed.
Simpsons produced in the 1990s is a completely different story and had tens of episodes that were masterpieces of humor, and most other episodes also being significantly funnier than even the most funny (least unfunny) episodes of the latest decade.
One of the masterpieces was the episode Team Homer. Here is the part that shows Mr. Burns using ether as a pain killer, causing him to hallucinate.
For those of you unfamiliar with the “Poppin’ Fresh” character that Mr. Burns imagines that Homer Simpson is, here is one of the commercials where it appeared.