There are offices that have legitimate reasons for requiring employees to be there at certain times. I've worked in secured locations that were all but inaccessible at 6:01 pm and you needed a good reason to be there after 5. In an environment like that, you can't stroll in at 10:30 because you prefer to sleep in.

A lot of folks on HN seem to have this idea that as long as you show up it shouldn't matter what time you get there, how long your lunch is, when you leave, or how many hours you are working vs. sitting on Facebook, and there should be this pure meritocratic judgment based solely on the quality of your work. Maybe that's ideal, but it's 100% unrealistic. In an office environment, showing up on time, not leaving early, and not taking a two hour lunch should pretty much be the minimum.