It's a funny thing. No one has to be told what's funny (to them) or not, in the same way many rely on authoritarians of varying dignitaries to tell them what's good or bad. If it's funny we'll laugh, and if not, we won't.
Well wait... I have to rephrase that. I have seen some who will actually look at another person to clue them in as to whether or not they should laugh. It's the oddest thing to watch. No, actually... (to me) it's funny.
The thing here is, this post was inspired by me wanting to distinguish between books I place on my keeper shelf, from those I lend over to the dynamic shelf. But I had to scratch that idea when I found myself running laps around a humor odometer trying to stop the dial on subjects that humor me. And just to note; nearly every book on my keeper shelf contains, either in the writing itself, or in the actual story, satirical elements. Some more so than others, and then others not at all.
Don't ask me why, because I do not know why it tickles many funny bones to see someone fall, or about to fall. And please don't gasp and say this is not you. I've seen it happen many, many times. Someone misses the curb, or croaks in a pair of stilettos sending the arms extended outwards, either eagle wide east and west, or straight up north. The knees buckle, either crisscrossed or bowed... sometimes both, and you'll be hard pressed not to find someone laughing.
Once there was a young man riding a bike down a regular one-way street, except he was looking backwards at a group of girls jumping double-dutch rope. I don't know what was so interesting about that, but when he turned around a second too late, and ended up flying over the hood of a car... well, the girls jumping rope doubled over laughing.
I was riding a bike once, BUT wasn't looking the other way... I was looking straight ahead, except unbeknownst to me I was riding without brakes. I ended up with a very nasty injury after in a vain attempt to stop the bike it ended up cartwheeling beneath me. Afterwards, I even had to laugh, and it took almost a month before I could walk again. Still, this had to be the funniest cartwheel ever seen attempted in all of its quizzical sardonic flips.
And someone else out here in this big paradoxical world thought it was pretty funny to trick someone else into riding a rollercoaster. And I know. How can anyone get tricked into riding a rollercoaster? But it happened. And to my defense, it happened at night. And yes, I saw the tracks and briefly considered why there was no water covering the tracks, but before I could put two-and-two together, so wanting to believe it was a water log ride, I was swearing to the top of my lungs how I was going to seriously hurt someone once I got down on the ground. —Oh boy, you had to hear the laughs.
So, you see, there is an odd subtlety working in the humor factor. Some things are plain funny, and then some things are NOT!