The military. It's ingrained in you from like day one that if you're not 15 minutes early to everything, you're late. It's also why you'll hear folks from the military talking about standing in formation waiting for 3 hours before the Colonel/Captain even shows up. By the time the order gets from the Colonel to the Private, everyone in between has padded the arrival time by an extra 15 minutes.

You don't clock in and out in the military, so sure, fine. And for job interviews, it looks good to employers. But beyond that, I'm in the "if you want me here early, you need to pay me for that time" club.

It's a common saying and it's usually meant as something you should hold yourself to, rather than others.

Staff Sargent - Military. Typically military peeps are held to a higher standard.