Nobody’s perfect. Some people come closer than others, but that’s usually because of good editing. In my case, I have proof: Here’s the fourth Crash Course Astronomy blooper reel, showing that we don’t just bang these episodes out. We have to edit them a lot.
Ironically, even these outtakes are edited; not all of them are funny. My editor Nicole Sweeney, only picks the ones that a) make her laugh, and 2) make me look like a dork. Her job is way too easy.