I hate:
"Just stop worrying so much." or "Just don't care."
"You're bored? You're lucky. I'd love to be bored. It's all right for some." (Yeah, I just LOVE feeling isolated and house-bound because of my anxiety. Lazing around on a bed all day every day with nothing to do, wishing I had more is such a lucky life! )
When people say someone is a "Loser." That word implies that they're failures in life and so fair game to be made fun of. That they're pathetic zeros. I hate it and find it hurtful.