There are times when developing where I find myself just staring at the screen. Despite knowing exactly what needs to happen next, nothing at all occurs. The next line of code just hangs there without an end, or that map remains an empty void. It's 1 in the afternoon and I've got lots of things set out to finish for the day, lots of high hopes. I look at the clock and it's suddenly 9 in the evening, so I look back at the screen, a single line of code has been finished. And then I'm angry with myself for wasting time.
Ever had one of those days where you can't get anything done? I'm not exactly sure what causes this loss of focus, but when it does occur, I know it's time to stop what I'm doing and give it some time before returning.