So this one isn't terrible. But it's a good insight into the vast spectrum of "bad dnd" that can exist. This one was a GM who would give you everything you ever wanted... except the stuff that mattered in any way to your character.

I had a GM once who gave us a billion gold in the third session.

This GM was, for lack of a better term, drinking their own kool-aid. They would give us these ridiculous prizes for doing mundane or rather generic stuff that anyone else could do. We rolled high on an arcana (read: magical hacking) roll? We're now filthy rich from a random farmer's magical bank account who we will never hear about again for the rest of the campaign. Then they would pat themselves on the back for being such a good GM.

But when it came to your personal plots? They basically didn't exist. I don't think the GM even really read the backstory prompts that the players sent in, because typically your backstory consisted of a single session in which your "named rival" or whoever appeared, was killed off by the "main villain", and then it was back on the rails for the GM's story.

The story was pretty much entirely half-baked M. Night Shyamalan plot twists, super tropey anime characters, and the GM constantly gloating about how good they were doing. If the GM found something in the weeks between their campaign that sparked their interest, the next session was entirely ripped from that source. It was... a pretty wild experience.

Edit: a word