Customer Stories 2

So this one is from several years ago. It was when I was a cashier at a local grocery store. Across the street was an old folks living center and they would come over all the time because they could walk there.
So every week on the same day, Tuesday, one of the elderly would come over. He was a crabby old bastard that would bring back his cans for the deposit from his last week diet cola twelve pack and use it towards this weeks twelve pack of diet cola. Every week last weeks deposit his total was $2.05 and he would then proceed to agrue it was $2 even.
Every week the cashiers would go through this, his yelling and arguing over the darn nickel. And it was never fun. And we always dreaded it.
Now I don't know why, but there are a few things that set me off and one of them is having a female coworker cry. I become very angry and do things not always right. Even if I don't like the particular person, I still become heated.
As it turns out, I did like this girl cashier and it was her turn with the old guy. We don't know what or why it was but he was in an even more cranky mood than usual. He brought her to tears and I became livid.
I walked up to her register took the old guys money and handed it back to him. I then grabbed the twelve pack and put it back on the shelf, telling him to leave and not come back.
He told me I couldnt do that and that he wanted to talk to my manager.
I told him, as far as he was concerned I was the manager (I wasn't) and that he was to leave and not come back. 
He huffed as he left and the real manager came up to me. The manager thanked me for dealing with that and told me to never do anything like that again. We never heard back from the old guy, don't know what happened to him, just hope he never bothered anyone like that again.