[Mr. Mojo]

the constant use of "like," as if it were a form of punctuation

I'd have placed that one at the top of the list. ....Although it seems to be (mostly) limited to the under-30 crowd.

[IAmNotAnAnimal]

Like, duh

[Signalman]

I am, like, totally sick of the overuse of the word "like".
Like TOTALLY!