The worst ones tend to boil down to: "As your manager, here is my subjective view of your performance over the last N months." which essentially rewards high visibility and self promotion rather than actual performance.
Second worst is: "As your manager, here is my subjective view of your performance plus 360 input from peers" which rewards your ability to join cliques and alliances.
Sadly in almost all jobs I've ever had, it was one of the above.
Sometimes the company would throw in a "self assessment," purpose unknown to me, which is likely not even read.
The ideal (in my view) performance assessment would be: "Here are the numeric metrics we agreed N months ago to measure your performance by. The data (collected neutrally and transparently throughout those months) show you met metric 1, 2, and 4, exceeded 3 and 5. Based on the transparent and mutually agreed upon formula, your raise and bonus this year are X and Y". Measurable and objective: Clear goal posts for you to aim for throughout the year. I've never seen this anywhere. I understand some sales roles get something like this.
VCs and shareholders don't come to shareholder meetings and say things like "CEO, I subjectively feel in my heart you are not doing a good job!" No, they look at the company's measurable, numeric results and judge by that. Why should it be any different with employees?
Obviously the hard part is coming up with those metrics so you're rewarding the right behavior and performance, but I'd much rather see companies put effort into coming up with those metrics rather than crafting the world's best self-assessment question or wasting everyone's time on 360s.