"Some writers worry that the reader won’t quite “get” the dialogue, and decide to spell things out, like this:
“I hate you!” George slammed the door and ran upstairs. He was furious with his mum – he felt that she was being unfair."
I have zero issue with this any longer. Pretty much every million-selling author I read bangs it home when someone is angry or sad, by telling the reader explicitly that they are angry or sad, to the extent that I figure they must be right. Because, millions.
Then I read the sort of optimistic advice that was linked above and I say to myself "That's easy for you to say anonymous nobody I've never heard of." I ball up my fists and shake them at the sky. Because I'm angry. Possibly sad. Or hungry.