The timing of office hours is always a matter of cunning strategy. I personally favour early morning on Monday and late Friday afternoons: Mondays have the added advantage of catching the bank holidays (always something to bear in mind when teaching duties are handed out too). I heard of one person here - well before my time - whose really weird crack-of-dawn 35-minute 'hours' turned out to be planned around the commuter flight to Berlin, where he was moonlighting in a second job!
I assume that in their imaginations, we're the Borg, waiting in our regeneration chambers when not actually lecturing. After all, we couldn't possibly have lives, could we? (Actually, I don't, and I generally do sit in my darkened office for extended periods, in some kind of stasis).
(TA = teaching assistant: postgrads who do all the real work in American universities)
What happens during office hours? Usually, nobody comes. Then the day before an essay is due, a queue will form. They will say things like 'could you go over it again'. I'll say 'what?' and they'll reply 'the last 6 weeks' lectures'. Some will express shock that you think they should read books rather than just cut-and-paste my Powerpoint into Word.
The other group of punters are those who turn up with a draft essay 4 weeks early. You read it in awe, then spend an hour explaining to them that yes, they've got everything right and they're well ahead of everybody else. These people are guaranteed to return every week to have their hands held because they lack the confidence and encouragement to realise how good they really are. The really arrogant and self-confident ones are the ones who fail. When I was teaching Study Skills, the only guy who came every week for a tutorial was a mature student who'd worked in PR over in Oman for 20 years. Once you'd cut out the advertising adjectives from every sentence, you were left with genuinely impressive insights into everything he touched. Only he never believed it and came back week after week for three years… Luckily, as well as being touchingly modest, he was also hugely interesting, so seeing him was something to look forward to every Thursday.