I cannot know about “horrible”, but at least many control-seizing attempts ended up bickering about who actually gets to control things. Anarchists vs Communists in Catalania for instance.

I’m guessing you’re not defining large-scale attempts at Communism like early Communist China and Soviet Union as worker paradises. Those experiments clearly led to worker suffering though.

Devil is in the details, a lot of seemingly conflicting things can work badly or they can work well depending on how well things are run day-to-day. And then there’s the problem that even if you start with a good system, you also have to maintain that system every day to the future or things will slowly (or sometimes rapidly) start going to shit. Some worker-controlled workplaces are good places to work, I’m sure, and some privately owned enterprises are as well.