I think that, in most cases, the annual performance appraisal "dance" is a CYA for companies that might have to go back and justify the firing of a low performer. Unfortunately, some of the managers (especially the low-middle managers) haven't learned to read between the lines and recognize that the performance appraisal is actually just a formality and try to actually use it as a club to beat more performance out of people who are already overburdened.
I like to give my best on what I'm working on, but generally dislike "Let's have a dinner/walk next time". That's what I have family and friends for.