When you're writing a song or a beat, and in the process of repetition, you lose the original idea for the sound that you had, and it all starts to blur together, and you start nit picking the fuck out of every little thing, and your ears start to hurt, and you start to feel a little crazy. It's time to back away from the song for a little while to gain fresh perspective.
Me: I've played this section of the song on repeat like 100 times trying to get it juuuuust right man! I'm starting to get producer ear!
Kent: Ok, time to take a break and come back to it later with a fresh ear!