Let's hypothetically say we have a young turk in a Japanese engineering department, where the unspoken departmental standard is 6 hours of work in a 16 hour day. If he works 10 hours in a 16 hour day, he is going to
quickly draw the ire of his older colleagues, because he is making them look bad. The boss will start cracking the whip and get them to meet or exceed his productivity, and then an arms race ensues. If, on the other hand, he works 10 hours in a 10 hour day, he is going to quickly draw the ire of his boss, because he is leaving six hours before everyone else, despite the project being horrifically behind schedule.
There is an entire genre of aphorisms to tell our young turk. Let's see: the nail that sticks up gets hammered down. The clever hawk hides his claws. etc, etc.
Work diligently, but with sufficient deliberation to achieve the company's exacting quality standards. Document your steps religiously. Hammer out hundreds or thousands of pages of specification documents, since specs always resemble forward progress. Teach your junior employees, who might be ignorant in the way of the world, how things are actually done, and most particularly how they are actually done here. With due deliberation.
Now, of course, my company was totally different, because we would never slack off like that. But, you know, I've heard stories of how things are done at places I don't have near-feudal loyalty towards.