Jason Fried, founder and CEO of Basecamp, said this in the HBR Ideacast podcast, which I didn't listen to but luckily there's a transcript:

You know, people don’t have hours anymore. Like, you don’t have hours at work. You know, people say they work 8 hours a day or 10 hours a day or 12 hours a day. They don’t. They work 15 minutes and 20 minutes and 25 minutes and 6 minutes and maybe 45 minutes if they’re lucky. And that just seems broken to me. So I’m trying to push hard against that.