I stare at this bug in my code continuously for ten hours and find myself none the wiser as it stares right back at me by the end of them. Electing to give in to the reasonable part of me (small as that part may be at times), I take a break consisting of a refreshing walk outside and a nice dinner. Afterwards, I sit back by my desk and mentally prepare myself to have another lengthy go at this pesky bug – except this time I spot the issue within minutes.
What would be an expression/term/idiom with which I could describe this state of "having tried to solve something for so long, that I'd benefit from taking a break and then trying again due to having developed a tunnel vision"? Alternatively: something to describe the "degraded state of my ability to perceive the problem" after having tried to solve it for too long. Sentimentally similar to saying that I should take a break and then look at it with "fresh eyes", but that sort of sounds more like I'm trying to ask for someone else's help (although there is a similarity between the two scenarios, except in that latter one a break is presumably just not enough).
To clarify: what I'm looking for isn't a way to describe exhaustion, but rather the state of having this temporary tunnel vision due to trying continuously for too long.
I've got something on the tip of my tongue so I'm pretty sure I do know some expression for this but I just can't remember.