"Awesomesauce" or lamesauce.
They both suck. No one cares. Go home.
That "bahaha" typed laughter.
If you make a "b" sounds at the beginning of your laugh odds are
you're a bad cartoon vilain or that you're spitting a bit.
"You're a [insert last thing that was mentioned and that makes no sense to say in this sentence]!"
(example: "You're a parallelogram!") It's not funny nor was it ever.
Honorable mention to: Anything that has an @ that isn't linking anyone or anything with a # that isn't on twitter, "Winning!", and any spoken references to memes (Bear Grylls is a clear exception but very hard to place in the right context so don't overdo it)