When I worked retail in NYC, I used to pack a lunch of either a sandwhich and some snacks, or leftovers from the night before. I used to label both my bag, and the containers my food was in as the breakroom only had one fridge and it got pretty hard to tell one container from the next. This particular day, I had packed some leftover pasta that I had made. I packed it as usual and put it in the fridge. I placed it where I always do, (so I knew where to look) on the right side in the far right corner.
After about 5 hours of gruleing work, I go to lunch. I. am. starving. I walked into the break room on my and saw a girl (that I had just heard complaining very loudly in a previous shift about how much she hates when people touch her Sh*t) EATING my lunch. Yes. She was sitting right there. At the table. Blatantly eating MY lunch. Not only that, she tried to lie about it! How did I know it was mine? The bag had my name on it. So did the tupperware.
I checked the fridge anyway, just to be 100% certain that I wasn't halucinating. I mean, no one is that rude right? Right? I open the fridge... check the corner...No lunch. So, in a fit of anger, I approached her. Right in the middle of the big break room. That was full of other employees. Right next to the managers office. (this was waaaay before my ehell days)
Me: Is that my lunch your eating?
Her: Uh, no. I brought this from home
Me: Really? Do you always label your bags with my name on them?
Her: So. This is mine.
Me: No. It isn't. I packed that this morning. You are either going to fork over some money, or I am going to go talk to Manager right now.
Her: What is the big deal? You can just go buy lunch.
Me: Excuse me?! Did you seriously just tell me to go buy lunch when you STOLE MINE!? You've got a lot of nerve! If I had that kind of money, I wouldn't have taken the time to MAKE my lunch today! You are going to pay me back or I am turning you in. I want at LEAST $10 for it. NOW!
Her: Fine.
(slams $10 bill on table.) Here!
Me: Let me ask you something. If you HAD this money the whole time, why in the HE** did you steal my lunch?!
Her: I was too tired to walk to the deli. What's the big deal?! YOU can go to the deli now! Stop your bit**in' already! Da*n!
The whole break room:

Me: Wow. You really are a bit**!
(takes money and walks into managers office to tell anyway) 
She was a *big* girl with a very bad temper and serious entitlement issues. Not a good combo IMO. I can't even imagine why she was still working there in the first place with her track record. I did get her fired as stealing is a fireable offense. Of course, it only works when it is reported...

Apparently this was not the first time she had done this, only no one else had the guts to call her out before.
(I know what I said was not ehell approved at all but I was young, angry, and I had not yet learned how to handle things like an adult.)