
There comes a point with almost anything i'm working on where it's just pointless carrying on with it. Where it all blurs together and becomes meaningless and I can't actually hold the whole picture together in my head any more. I hit that point at 4:45 yesterday afternoon, where the test plan I was writing ground to a halt because I couldn't grasp the flowchart any more (despite the fact that I'd written it).
I don't tend to work overtime if I can possibly avoid it because 95% of the time there's no point. If overtime meant I could work until 4pm, wander off and do something else for an hour and then come back to work 5-8 then it might be productive, but me sitting at my desk from 1pm to 7pm means I get exactly the same amount of work done (roughly 1-4, depending on how my concentration is) and then sitting at my desk for the next few hours getting more and more frustrated and failing to get anything done.
I'm actually fairly sure that most of my work happens subconsciously, when i'm doing other things. I'll grind to a halt on a project, go and do something else for 15 minutes, come back and the answer to my problem will be sitting waiting for me. Sadly, there's no way to explain to management that not only ca I not really explain how I come up with answers, I don't really know most of the time myself (sure, I can explain the logical reason why my answers are right, but that doesn't mean I came up with them using a conscious, logical process in the first place). If you're not sitting staring at a monitor, pressing the occasional key, then apparently you're not being productive, an ideology which (for me) doesn't fit the facts even slightly.
It's exasperating and infuriating to have to deal with people for whom it is true, but there's not a lot I can do about that, short of continue to work my way up until can find a niche where I'm judged on my productivity and not on how hard I can look like I'm working. Fortunately I rarely have to deal with that kind of thing in my current job, the attitudes there being generally quite enlightened.