There is a young lady that sells food at my workplace. She loves people patronising her and she doesn't mind going round offices to ask if you've eaten, especially the men. One day she came to my office and all the men said they ate before leaving their houses. To their greatest surprise the lady was furious. "Why are you stressing your wives? You wake this woman up very early to prepare breakfast? Why do you have me here? I'm here to serve you. Please allow me to serve you. Tomorrow, don't wake your wives up. Let them sleep very well. You have me here to worry about your breakfast. Without you, there will be no me.". Talk about salesmanship or perhaps a clown because she got everyone rolling with laughter.
I bet you also found it funny reading it. If you don't perhaps this would make you laugh.
My younger sister is still single. Recently she met a man that said he was falling for her on dm and she replied, "please stand up and stand on your two legs. No falling because I won't catch you".
This is how effortlessly humourous some people can be.
I consider anything that makes me laugh, humour. It can be spoken words, live actions or perhaps in a book or a movie. Humour sometimes can be preplanned and other times can be accidental.
Just like in the case of 
Then I went to sleep, my belly was very big, as if it had been pressed. And what was my biggest surprise that I could not sleep, I began to feel pains in my stomach, cramps, I wanted to vomit, I felt dizzy. And I started screaming: -I'm dying, I'm dying, help.
Humor is an instrument that can be used to liven up a situation or make an event more enjoyable. This is why comedy is a thriving business. A life without humour is a very boring life.
I would say humour have limits but it also depends on the person making the humor and the recipients. All humour is intended to do is to make people laugh but the moment it is doing the opposite then it has crossed it's limit. Humor can be anything but when it comes off as norm-violating or places certain pragmatic demands on people, it has crossed its limits and such an attitude may not be tolerated. Take for example, the recent occurrence at the Oscar between Will Smith and Chris Rock.
While trying to be funny, people's personal life, struggles and challenges should be respected. Even comedians can get sued for their jokes. Recently a popular skit producer created a skit that projected nurses as sexual objects. The nurses association found it offensive and publicly demanded he take it down or face legal actions. The comedian immediately apologized and did as he was told. This is because humour has crossed its limits where that profession is concerned. Such skits might be made about another profession and they won't take offence.
I love humour but I prefer light humour to dark humour. I do not want anything that will leave me thinking I'm a sad and twisted person to be laughing at something so horrid. Dark humour can lead to religious or interracial war. If something is a taboo then those that made it so wouldn't find it funny that someone is making a joke out of it. Most comedians I know thrive on good humour. You don't go telling dark humour on an occasion, you just might be thrown out.
Talking about dark humour has left me with goose pimples. Memes are great ways to make people laugh. 
If you ever think you are having a bad day, just think about me that went to a restaurant with a headset playing loud music and forgot I had an headset on when my stomach trouble started while I was eating, I needed to let out some gas. l let out the gas when the music was playing at a high tempo thinking no one heard me until someone angrily removed the headset and I was faced with angry looking eyes from everyone who came to eat at the restaurant.