N=1, but this HNer seems almost opposite from you. My biggest problem is getting started, and maintaining focus for the initial period of 15 minutes to one hour (for some reasons I get really anxious; despite a decade of trying, I still haven't learn how to manage it). But once I get past that hurdle, I can get a lot of high-quality work in short time.
>I have no trouble getting started, I have trouble stopping.
I can relate. It has its pros and cons. There are definitely days I wish I could turn the ambition off or at least down, but it's stuck on high. The upside is life's never boring. The downside is it's always non-stop.
I likely mistakenly assume most HNers are overly ambitious, perfectionist, neurotic types like myself.
I have no trouble getting started, I have trouble stopping.