Not necessarily. I did that for a while at a job I hated. It was the only thing that kept me sane. Lots of hackers (like me)
hate confrontation. Even small amounts of interpersonal conflict cause intense discomfort. So, when under a toxic boss, I think adopting a clockwatcher attitude is an entirely valid strategy.
I analogize it to the strict shift rotations employed by nuclear reactor workers, chemical plant workers, and others who have to deal with dangerous and toxic materials in their day-to-day jobs. You set hard limits on exposure and stick to them. The act of setting and sticking to those boundaries can give you a modicum of control over a situation where you feel like you have no control at all. It can make a huge difference.
And, of course, as a side benefit, setting hard limits on the hours you work also allows you to have time to conduct a search for a less terrible job. :)