Humor is subjective. But I think, just like art, there is something inherent to it. Something that makes a joke objectively good or bad, even across time and places.
I could just not describe it, but I read some old jokes (Old jokes. Like, ancient Egypt and stuff) and they are still funny!
Indeed it is subjective. There will always be those heckler types. In a conversation I can be incredibly dry with my humor and just say things. Three people will laugh, one gets angry. Some people can only be funny by telling jokes they heard. They might think they're funny for doing that but it's actually the joke that's funny and they had nothing to do with it. Regardless of the delivery though, laughter is one of the only true reactions left in this world that cannot be faked... unless you're part of a laugh track.