Design myopia is a term I've coined for moments when I've spent too long on a design problem and get stuck. Once you've worked on a design for too long, everything starts making sense to you. After more than 3 weeks working on a project, it's likely that you have a hard time finding the weaknesses in your design. (especially if you've made it this far and have already put it in front of other people's eyes)
Design myopia is really a serious issue. As you get to the final 10% of a design, you can easily spend 25% of the total project time tending to these final details.
Some common psychological issues that arise toward the end of a design is the fact that you feel like an expert. If other people are confused by some small details in your work, it's because they don't think like you (you tell yourself). They haven't spent as much time as you have on this project, so they just don't get it.
In these situations, it becomes imperative that you don't continue forcing your way to a solution. In one instance, I walked a colleague through my screen flow and explained areas where I had been stuck. I explained the precise parts that users had experienced some confusion. Within 20 minutes, my colleague made a small change that I hadn't considered and helped me get to a more elegant solution.