I wonder though how many of those increased hours go into actual work. I'm sure some amount does, but how much time do you think the typical European office workers spends on a Reddit or Facebook as opposed to an American one.

As an American, I've worked at a "good" company in terms of expectations of hours and "bad" where one would want to come early and stay late (and make it known on the team chat) if only for appearances. I can say anecdotally that my amount of time slacking off increased with my time spent in-office at the second company, and from walking by, it seemed the case with others as well.

Honestly, what with software being salaried and exempted from any overtime, what incentive do I really have to kick out an extra couple hours a day?