Strong Bad of Homestar Runner is a Grammar Nazi... which doesn't stop the fact that his grammar and spelling isn't perfect either. He has also said that he "doesn't wear underwear"... which has been proven wrong numerous times.
In Baddest of the Bands, Marzipan complains about people who ruin the environment... as she tosses litter on the ground.
In SBEmail "web comics", he talks about webcomics that is based on reader input, which he decries as a cop-out, despite his series being just that.
In still another SBEmail, "the movies", Strong Bad gripes about people who won't stop talking during movies. At the end of the email, he watches a movie on his computer, done in ASCII art, he starts talking during the movie. Realizing what he's doing, he says softly, "I'm kind of a hypocrite! I'm gonna shut up now." During the actual movie at the theater, however, in response to everyone talking, he actually yells at everyone for doing so, even though the email mentions nothing of the sort.
Strong Bad: "What is wrong with you people?!? Do you not notice the giant movie over here? Were all the local sit-around-and-suck-out-loud places closed?!"
Yahtzee did this at the end of his review of Silent Hill: Homecoming. His rant was even copied and used after the credits of his videos for quite a while as advertising.
Fans are clingy complaining dipshits who will never ever be grateful for any concession you make. The moment you shut out their shrill tremulous voices the happier you'll be. Incidentally, why not buy a Zero Punctuation T-shirt?
Another example of his blatant hypocrisy: In his review of Duke Nukem Forever, he calls out companies who "get paid to do a job [they] didn't do," and says that they deserve to get sued. As he is going through this rant, he shows that his contract with the Escapist is to "Review Actual Games That Exist," and he himself is breaking that contract.
Yahtzee uses this throughout his entire series, such as calling out "self-important bearded tosser who read too much into things" and then admitting that he's the biggest one of them all.
His review of Super Mario 3D Land becomes this when, due to rage over Mario, he decides to review Rayman Origins instead. His first order of business is to talk about how no one could care about characters whose heads and appendages are disconnected from their bodies... while adding stick limbs to his own, similarly designed characters.
RWBY: The battle between the heroines and Roman in "Painting the Town" ends with an amusing example of this, when Yang admonishes Weiss for making a bad pun. Yang of all people. Yang's viewpoint is somewhat reasonable considering the girls had once again defeated Roman but failed to apprehend him.