To hate it when people point out spelling mistakes and typos.
People ask for advice when they are worried, unsure etc and the first line of the first reply is about a spelling mistake. How is that helpful or supportive.
Typing on a phone screen , as I'm doing, is guaranteed to cause mistakes. Also the person may be dyslexic or out of practice.
Let people ask for advice free from criticism.
Rant over. I'm sure this post will now be scrutinised for errors.