I imagine it's a common problem! I am definitely with you. I think that's a small part of the reason that I end up signing up for so many exchanges. It's helpful to have a deadline and know that someone is counting on me. When I'm just writing for me, it's easier to procrastinate.

of course then i look at those words and think "ugh, this is so flat...." but at least they're out.
I get that and have felt similarly. Sometimes I walk away and give it some space and when I return, I'm like "oh it wasn't as bad as I thought".