I have a pet peeve. It is something that drives me insane. I am constantly yelling corrections at the person on TV who has offended me.
People who earn a living by speaking should be able to do it correctly. The words establish, ask, escape, especially, escort, escalator, espionage, and espresso (to name but a few) have no "x" in them. Look at them. Not an x in the bunch. Yet people who should be educated enough to know better constantly say "extablish, ax, excape, expecially, excort, excalator, expionage, and expresso". As Lucy would say in Charlie Brown, "AAAAARG!"
Problems with pronouns is another peeve. For instance usage of I/me are constantly confused. You would never say Me have a necklace. That is not a problem. I have a necklace for me is also not confused. Why then do folks insist on saying, "I have a necklace for he and I"? I is subjective while me is an objective pronoun. I is the doer of a sentence. Me is the receiver of the action. Try it with he/him. He has the necklace. The necklace is for him. Easy enough to remember.
Then there are what my teachers used to call modified oaths. Rather than say Hell we would say Heck. What we said were not considered to be "bad" words. But they replaced bad words. The most annoying word I hear is Fricking. If you mean to say it then SAY IT!
I am not above grammatical faux pax. You may notice that I do not use punctuation in most places. That is by design. I know proper punctuation. I choose not to use it because my typing skills are so poor that punctuation takes me a lot of time.
How about calm. People have begun to pronounce it as call-mm. It is pronounced com. Look it up. Often is in the same category. It is pronounced off-en. The t is silent.
And do not get me started about nauseous. If you are nauseous you are causing nausea. In other words you are making me sick. If you have an upset stomach you are nauseated. Someone else has made you sick!
I have a major grammatical flaw that drove my mother crazy. I say things like "A whole nother thing." Mom corrected me every time she heard me say it. I have no idea why I say it and I know it is wrong but say it I do.