(Editor’s note: this is a response that I posted on Quora, and is clearly subjective. Feel free to share your “vote” for the worst in the comments at the end)
Well, “worst” is frankly a matter of taste.
“Least popular” is almost certainly Joe Besser. He was the least “physical comedy” of the Stooges, and appears (overall) to be the least popular Stooge. Although, it should be said, he was a funny fellow. I’ve enjoyed him on The Joey Bishop Show, The Abbott and Costello Show, and other places.
Curly for President T-shirt
Some people would argue that Curly Joe DeRita is the “worst” Stooge — but I disagree. Curly Joe was funny, as well as sweet. No, he’s not Curly, and he’s not as active as Curly was. But people forget that, by the time Curly Joe joined the act, all Three Stooges were in their 60’s. For what it’s worth, I laugh at Curly Joe’s antics in “The Three Stooges Go Around the World in a Daze” and “The Three Stooges Meet Hercules” — something that I really can’t say about Joe Besser’s Stooge movies.