Really? When I complained about Firefox performance on macOS, I was downvoted by a lot of people. It almost made me consider if the problem was PEBKAC (problem exists between keyboard and chair). I am glad I'm not the only one. I wanted to love Firefox, but I can't because of this.

edit: reading all the comments in this thread, geez, I finally feel like I'm not a stupid user. :) The issues are real!