Some psychologists will suggest that this drive for perfectionism and being highly detailed is one of the many ways anxiety manifests itself. It certainly is a double-edged sword. Are you concerned about how your peers or co-workers perceive you? Take the extra effort to perform better than they do. Know more than they do. Don't disappoint anyone. Receive praise for high performance. Set yourself apart. However, go a bit too far with it and it socially isolates you. You become intimidating to them. Story of my professional career.
Perfectionism can also be one of the ways obsessive compulsive disorders can manifest itself, as well. You are so concerned that everything must have its place, that ritualistic behaviors manifest. Order and control. A right way and a wrong way. Check and double check.
These behaviors are often filtered through the amygdala's, the brain's "fear centers", and highly influences day-to-day decision-making and behaviors. Anxiety, controlling behaviors, OCD, perfectionism, are all behaviors filtered through those amygdala's.
I can say I am the most relaxed, chill person in the room. I certainly do not feel anxious, but then, all of those behaviors present themselves.
@pottyfry "I need some time to relax, because all I've been thinking about is writing, writing, writing. Got any tips for taming perfectionism and coping with it?"
You found your answer. Anxiety and stress. Remove yourself from the situation, both physically and mentally. Clear your head. Go to a park, a museum, walk around outside, fishing, whatever that is for you. Get your mind focused on other things for a bit. Then, come back to your writing with a refreshed brain. That said, in my experience, you're still going to be a perfectionist. Just limit it to things that really matter. For me, it's my job. When I am at home, I still have those tendencies, but I can relax and give myself some grace because it's usually things I "want" to get accomplished rather than things that "need" to get accomplished. If you are the only one judging the final outcome, relax. If things really matter, like seriously really matter, then demand perfectionism.