Perfectionism... I often refactor my code because I always see something that could be "done better" in my own work, which can slow me down if I'm not paying attention to my main task.
If I could stop time I would perfect my code all day, but that isn't realistic. 😂

Doesn't apply to dev work only, I've had to learn the art of not giving a shit about every single detail in many other disciplines. I just love getting things done really well.