I am a slow sewer. I take weeks or months to plan a project, working out details in my mind and in a sketchbook. When I do sit down to sew it's for as long as I'm interested. Running into a tricky detail, needing to adjust fit, feeling tired, are all reasons for me to take a break. I don't have the stamina that a healthy person does.
I find cutting tedious, sometimes tricky and it hurts my messed-up neck. Cutting is scary: you start with unlimited options in the piece of fabric but each cut is a potentially ruinous mistake! I really need to get over this fear and remember that it's only fabric.
Sometimes my slowness has benefits. I'll think of a better way to complete an item, or solve a problem after subconsciously mulling it over. A faux suede jacket I started a few years ago is still in pieces. Because of this project I read as much as possible on tailoring and fitting. I learned many new techniques. It was the first muslin I made.
Halfway through I decided to interline the jacket so it would be warmer, thus more wearable. Going back to it this winter I realized that the lining was cut to the same size as the (stretch) fashion fabric. I now know that the lining needs to be cut larger, with a pleat at center back, etc. I was given some fun pink silk that should be perfect for the lining. I now have a large rotary cutting mat and serger so silk doesn't scare me ;)
Other times I frustrate myself. The suede jacket could have been done two years ago if I'd just done it! In striving for perfection I created nothing. Now I'm trying to accept that good enough is just that.