When I got my first office job I realized the huge differences.
I'd been a laborer and when you labor, you have to buy coffee during breaks.
Then I became an office worker, and when you office-work, you drink free coffee while working, then relax on your breaks.
This difference is really quite vast. Those who buy their own coffee make less and work the whole time during work. Those who get coffee make more, and can find ways to skirt work, like by reading the news instead of doing their job, for example, or emailing a friend instead of emailing for work.
There was a Saturday I went to my office when my home Internet was out. I had the place to myself, and did my schoolwork while eating pizza, drinking sodas, and then walking out with a coffee – all for free.
Had I still been a laborer, I'd have had to eat lunch, then sneak a drink into the library where I wouldn't have had as much ease and freedom.