This is a pretty fraught area. As the comments show, there's a lot of emotion, and cultural differences at play.<p>"Cultural differences" can be macro, like, in Japan, a 10-12-hour workday is <i>de rigueur</i>, and it can be "micro," like individuals that have different clocks.<p>I had an employee, who is, no exaggeration, one of the best engineers I've ever known. But he couldn't come in early, to save his life. He'd roll in, around noon, but would often stay until 2AM.<p>The Japanese loved him. He was often on their time zone.<p>American HR hated it, and I got called on the carpet, numerous times, as his manager.<p>But I stood up for him, and let him do his odd hours, even though it cost me. Fortunately, Japan backed me, and they were the ones in charge (that didn't win me any friends on this side of the pond).<p>I have been "retired" for the last six years. In that time, I have worked harder -and far more productively- than I ever did, in the workforce.<p>The key seems to be, as has been alluded in the comments, mastery of my own schedule.