The thing is that there is plenty of work that isn't due on a tight deadline right now, but takes time to do. In these cases, why should my boss care if I decide to work noon to 8pm instead of 9 to 5? My boss doesn't care. I am my boss.

The measure of a good knowledge worker though is not being on time, rather it is productivity month over month.

If it's due at 5pm and takes all day, no one is waiting on you at 9am.