One summer I got the opportunity to work as a bus boy for a touristy joint down at the beach.

One of the greatest jobs I’ve ever had. I didn’t have to learn the menu or deal with irate customers when they discovered the “Fresh Grouper” was actually Vietnamese Amberjack, yet I often left with as much money as the waiters.

It’s the only place I’ve ever been recognized as “Employee of the Month.” The plaque with my name on it disappeared in the aftermath of Hurricane Ivan, but that’s another story.

I quickly realized that there’s an interesting relationship between the bus boy and the wait staff. Sure, we get the same minuscule hourly rate, but instead of getting tipped by customers, bus boys get tipped by the waiters & waitresses.

So at the end of the night, each waiter would owe the bus boy a percentage of their sales from the day. Typically $12 or $13…maybe $20 on a good day.

Being the anti-confrontational soul I am, I’d never question the waitress who owed me $12 and only gave me $10. Nor did I complain when the one who owed me $17 would give me $20. I just took notice, and figured it’d all even out in the end.

As I started paying more attention, it became clear that I wasn’t the only one who noticed.

The waitress who consistently rounded down began having a hard time getting her drink orders from the bartender (who also relies on tips from the wait staff). And she’d turn 2 or 3 fewer tables per night, because her tables wouldn’t get cleaned as quickly.

And just like that, without her really even knowing what happened, she was making half as much money as the others.

The ones who rounded up by a few bucks, however, knew how the game worked. It may have cost them an extra $3 that night, but the next night their tables would be bussed immediately. They’d get sat 2 or 3 more tables than the cheap waitress over the course of a night.

That extra $3 investment she made in the bus boy? An extra $20 or $30 a night in tips. Not a bad ROI.