Top two:

My current coworker: As much as he can be a nice guy, his claims about why he can't show up are outrageous. He texted my boss how he slipped and fell so hard that he cracked a tile floor with his head. One day he demonstrated his distress about waking up with kidney pains with exclamation points after every!other!word! My boss would have already fired him if we weren't short-staffed.

A few years ago my boss hired a kid I graduated high school with; I didn't know Phil, but we did get along. Phil also had a job installing granite counter tops with a local company, so Phil assured us that his day usually ended by 5:00. He and my boss agreed that he would call as soon as the day was over so Phil could head into work with us. She would record the time he would arrive, and by the time 10:00 pm closing rolled around, all employees would leave together.

After almost two months, it became apparent that Phil was using the excuse that "we got put behind with jobs" so often that he was working two hour shifts instead of 5 hour weekday ones. Phil was also required to work five hours on Sundays, although he became pretty salty when his request for all weekends off in the summer was denied. He wasn't generating substantial paychecks as a part-time employee, yet he felt that he should be compensated for the time he should have been working with us while he was on granite counter top duty. After he bitched about one of his paychecks amounting to $86 and change, my boss adjusted the amount. She had not recorded the time he arrived, yet Phil claimed that he came in "at 5:00" when it was really later, only I couldn't recall the exact time.

So I began keeping my own up-to-the-minute log of when Phil was really arriving. When he would complain about a check, I would consult the log; I never told my boss what I was doing. I ended up recording a month's worth of entries without incident, until the Tuesday Phil called that he was on his way, yet never showed up. At the end of the week on payday, he bitched -- again -- about his check, this time it was for over $50. Phil claimed that he was there all week and arrived early, yet when I looked at my entries, he had only been there for an hour each day after Tuesday.

I brought my log book to my boss's desk and showed her Phil's time tables. It was enough to make her decide that she was firing Phil on the spot. Then Phil tried getting me to vouch for him and I simply replied, "Sorry, I can't help you. You should have showed up."

tl;dr: First story: Coworker #1 makes up stories about why he can't come to work. Second story: Coworker #2 tried gouging hours, so I kept tabs on him and caught him in a lie which got him fired.