When I was in my 20s, I worked at a gas station. My starting pay was a nickel over minimum wage and went up by less than a dollar over four years.

Timesheets were hand-written, and I didn't know how closely my boss was monitoring things to see how accurate our self-reported times were. It was a small place, such that only one cashier was on duty at a time. So my shift wouldn't end until the next shift showed up, which could be early or could be late.

So I developed this concept in my head called "timesheet karma," where if I showed up a few minutes early or worked a few minutes late, I would not report the extra time and thus not get paid for it. My logic was that if I built up enough of this karma, I could be forgiven if I ever showed up late. Which I occasionally did, but never enough to cancel out the total time I worked without pay all those years.

In retrospect this was insanely stupid of me.

Nowadays I work at a place with an electronic punch-in system. I quickly noticed that it rounds my time to the nearest quarter-hour. So now I intentionally game that system to squeeze a few bucks out. If I am leaving a few minutes after the hour, I'll linger until the clock reads exactly ×:08, so my punch-out is rounded to x:15. And I try to punch in early enough for my punch-in to be rounded down. I'm already criminally underpaid so I have no problem using the system to pad my hours a bit.

Learn from my mistakes. Don't work for free.