Although I am no language expert, there are some grammatical errors that drive me batty.

My pet peeve is when someone mixes up ‘that’ and ‘who’. So many people (even some journalists) don’t know to use ‘who’ to refer to a person and ‘that’ to refer to a thing. I read “He is the type cyclist THAT will ride all day.” Drives me nuts. Don’t know why.

Correct usage is “It is the kind of bike THAT will last for years” and “He is the kind of cyclist WHO can ride all day”.

I don’t personally correct anyone when I see this, but I wish I would sometimes. Maybe the people WHO make this mistake will read this and understand.

What is your pet peeve when it comes to grammar and spelling?