Do you have a friend or relative who does something really minor but VERY irritating?

I have a working doorbell. For as long as I can recall, my mom refuses to use it. She always just barely knocks with one tiny knuckle on my door. Unless I am right next to the door, I never hear her knocking. She has actually left my house while I was waiting for her because she assumed I wasn’t home. I couldn’t hear her microscopic knock!

So what is minor but annoys YOU to no end?