Or is it?The World's Largest Man and I'm Wearing Tunics Now. But with Sorry I'm Late, what we have is not an account of some part of someone's life, their past. What we have is an account of planned experience. There's nothing wrong with that. Other books have been written with this kind of set-up. It looks as if A. J. Jacobs has written a number of them. (Perhaps he's someone I should read. There are so many someones I should read.)
In my study of humor writing, I've learned that one way to find material is to look to life lived. Sorry I'm Late, which is definitely funny, teaches that we can also create material. Because what Pan did was spend a year saying yes to a list of experiences an introvert probably wouldn't embrace. I suspect a lot of extroverts wouldn't, either.
As a self-identifying introvert, I expected to find essays in Sorry I'm Late on, say, forcing oneself to engage with people after yoga class or to speak to people---everywhere. But what Pan did was say yes to things like performing on The Moth and taking a stand-up comedy class that culminated with another performance. I had trouble wrapping my head around her choices of activities, I guess because I found them to be things that even many extroverts wouldn't attempt to do. Personally, I won't even listen to The Moth, because I find it depressing. My comedy fantasies don't run to doing stand-up, but working in a comedy writers' room. From home. On-line. Without having to be in the same room with my colleagues.
Of course, that may be the humorous hook here--the incongruity of an introvert wanting to do these things.
A couple of days ago, I signed up for a 30 Days of Positive Thinking Challenge being run by a meditation app. I realized while working on this post and analyzing Sorry I'm Late, that I might be able to do some humor writing around that. In which case, like Jessica Pan I would be generating material with something I'm going to do, instead of finding material in something I've already done.