For me, it's also anxiety. But lately I've come to realize that it's a symptom of me not knowing some component of the task. For instance, I've been putting off building a coffee table for the house. I just found out that wipe-on polyurethane exists yesterday, and it seems to be the answer to my lacquer problem. I'm already feeling a lot more likely to start working on it.

I've had other similar issues when working on our house in the last year, and they were all solved by finding the solution to something I didn't know how to do. Then I suddenly had the drive and energy to do it and knocked it out quickly.