As a person I believe just about anything is funny if done the right way, but here are a few examples that always make me laugh
  1. Super high level intensity on things that do not need any intensity
    Ergo people screaming about how incredible some small food, slapstick level of outrage over simple things. Like when people play up the sheer amazingness of common household items. "YOU WOULD NOT BELIEVE JUST HOW MUCH FRUIT MY JUICER CAN JUICE IN A 36 MINUTE PERIOD!!!"
  2. Use of completely arbitrary numbers and specificity
    Like someone is using percentages to say how sure they are; "I am 64.75267% sure". Like that's entirely unnecessary and I love it.
  3. Completely wrong guesses for obvious answers
    How many stars do you think are in the sky? "Idk, like 14? Maybe 15?" Classic comedy tbh.
  4. Any and all sarcasm, especially when delivered deadpan
    Sarcasm is the epitome of funny
  5. Calm and casual existential despair
    "Whaddya wanna do today?" "I don't know man, maybe die. That'd be chill". It's the calmness and uncaring that does it for me