Disclaimer: Did not RTFA. There is a difference between observation and judgement. Sometimes it's easy for people to separate the two. For example, let's say

Disclaimer: Did not RTFA. There is a difference between observation and judgement. Sometimes it's easy for people to separate the two. For example, let's say I am drawing a picture. I draw a line. It is a line. It's neither good nor bad. It's just a fact. The line is not straight. Again, it's just an observation. The line is not straight enough. Here I'm comparing the observation against some ideal. It's a kind of discrimination. When drawing a line in this circumstance, there is some advantage to it being straighter than the line I drew. This has an air of judgement to it, but I can still view it objectively if I fully understand the advantages and disadvantages of making the line more or less straight. I am bad a drawing. This may also be true, but we're slowly making our way from a helpful objective comparison to an unhelpful judgement. Against what criteria am I bad? Do I need to be better than I am? I should not draw because I am bad at it. Now we're making a lot of implied judgements and making conclusions based on a lot of things that we haven't necessarily thought about. What's wrong with drawing badly? Why should I avoid it? etc, etc. So in that way, the stress is not inherent in the "perfectionism". It is not stressful that a math question may only have a single defined answer. It's not even inherently stressful if I don't know the answer. It's only really stressful if I think I should know the answer, or if I'm pretending to know the answer when I don't. There is nothing wrong with thinking critically. It's the assignment of value where it becomes problematic.