Ah.... the zone. That fabled place where we are tuned in to our work, where we're humming along with our system, where synchronicity and productivity bloom.
Beware the Zone
A zone is a temporary communion with your work, yes. But a zone is also a circumscribed place, a place that by definition has boundaries and edges - like a tunnel. A zone is characterized as much by what you do not see as by what you do see.
Many of the bugs I've found, and most of the really serious behaviors I've been able to characterize have started as a distraction. They weren't part of the test I was doing, but rather something that made me say, "hmm, that's funny."
When you're in the zone, you tune out distractions. That means you aren't seeing the guys across the hall playing basketball with a trash can, sure. That also means you're not noticing the odd setting in the log file that isn't what it should be.
It feels great to be in the zone. So let yourself go into it. Just don't stay too long - and ask yourself formally what sidelines you should be pursuing. It takes time to learn, but make sure that anything you accomplish includes the question, "and what else interesting do I see?". If you ask it formally long enough, it'll enter your zone, and then you're really testing.
Leave the basketball players out, but try to make sure the log file oddities are within your zone. After all, we're testers; very little we do is narrow. So let's make sure our zone is good and wide.