I had this issue with a developer once: We were at a hackaton, and I made a quick-and-dirty feature (we had less than 6 hours left). The other developer on our team got pissed because the code "sucked" and spend a full hour refactoring it...

While this is an extreme, I think every developer is a perfectionist in one area or another. This can be a disadvantage when you're working in highly unpredictable environments (read: business) and where a simple quick-and-dirty MVP will do the job.

So their tendency to be a perfectionist (in situations where this is NOT the optimal mindset) is my biggest struggle when working with developers.