Years ago, I had a cleaning and painting business.
I worked for property managers and I had a small window of opportunity to get into each unit I was hired for and get it ready for the new tenant. It paid well for the hours allotted, but I found I wasn't fast. I cared too much what the end result looked like. I simply could not make myself do a crummy job and that's all I was given time for. I never missed a deadline but I was constantly stressed by the crunch feeling. I grew to hate it.
I started resenting and grumbling while I worked, then it grew to a running resistance going on in my thoughts all the time, even when I wasn't working. Even today, that thought pattern can come up if I'm doing similar work, like when I painted my new house last year. I caught it very early and had a blast painting, even with a tight timeframe. Thoughts are everything, as you know.
Nowadays I know more about myself (because of that experience and others like it) and I work plenty of time into my projects. I let people know that a great job takes more time then a crummy job and it costs more. I only work with people who are interested in quality. Plus, I deserve the time it takes to do my best work!
We perfectionists create interesting times for ourselves when we try to fit our style into someone else's time frame. Remember that all experience has value, and with practice, we can do a great job faster. But only if we keep a positive thought process going as we do the work.