No matter how cool a parent you may have, they can never pull off using our generation's slang. They should stick to phrases like "groovy dude," "the bee's knees," or whatever they used to say. No one wants to hear their parents talking like a Jersey Shore cast member. It is even worse if they write the offending modern phrase on the Internet because then it becomes very difficult for you to ignore it and pretend that they never said it in the first place.
9. Misusing The Lingo