Sam was always funny in his own weird parochial way. Like I couldn't even really explain to you why the classic iPhone and mirror videos are so funny to me, it's just mocking/being self-aware about a certain kind of guy/attitude and articulating that in such a funny way.
Really he's more funny as a performer than he is telling jokes. I also find it incredibly ironic that Harland needling him and fucking with them in the same way that they've spent a solid 1/3rd of the skits of EP doing to random actors they found on Craigslist got to him so hard. It's easy when you're the hammer but nobody likes being the nail I guess.