Shouldn't we be rude at times?

Maybe it is just me and the curtish way I tend to go about things, but I think being rude is necessary at times.
Yes, I have an example.
Maybe a year or so ago, I went to pay my cell phone bill. For whatever reason, I chose to pay it in the local office.
People think the Post Office is an awful place to wait in line...no, no...try waiting to pay your bill in a room full of people pretending to be interested in buying the latest phone, knowing they only have $25 bucks to spend...it's a hell dreamed up by Spanish Inquisitors.
So, there I was, just off work and not wanting to be bothered. When I walk in, what do I see?
There is this beast of a man ( clearly a customer) sitting at the counter yapping away to the clerk who is trying help some non-English speaking couple understand why their 32 crumpled dollars isn't enough to pay the $75 bill they have.
Beast Man has, spread out in front of him, his Subway paper "plate" which is erupting lettuce and olives and only Lord knows what else onto the counter. He has a stool pulled up to the small customer service area and has not a single care in the world.
He was having such a good time...
Apparently, he seemed to think the clerk (certified customer service specialist) was really listening to him. At first, I was somewhat amused. Then, I realized I would soon...if God is good...move up in line and pay my bill...but, I would have to pass Beast Man.
As I aged slowly and the couple left, not sure why the man wouldn't take their money, I eventually moved closer.
Beast Man turned and looked at me.
"Just get off work?" He asked, quite innocently.
I nodded. (For reference, my job is not the cleanest of occupations. This day was one where I had been soaked from a broken water pipe and I was covered in mud...on top of that, I was still wearing my hard hat and vest)...I knew at once, this guy was a real sharp one.
"Long day?" He asked.
"Yep," I said. "And it seems to be getting even longer."
Beasty had no idea I was referring to him and laughed heavily. The crumbs resting on his breasts puffed in the air like dandruff. I knew, without looking, mayo or oil or goo would be slather all over his chin and poking out the corners of his mouth...I was right.
"So what do you do?"
I sighed, "I wait in line at stores for a living." What do I do? I am covered in mud and soaked...what kind of question is that?
As I moved ahead in line and finally got to the counter, he had asked if I was married, what city I lived in, and several other "how's the weather" type questions.
In a moment of timing military sharp-shooters lust for, a surplus (it seemed like half a head) of lettuce fell from his dining area and onto my boot...just as I stepped to the counter. I said nothing, only looked down at the handful.
"Oops!" He laughed and explained how much he hated the amount of lettuce Subway put on their sandwiches. (did he not realize you can say "hey, easy on the lettuce" to the sandwich maker guy?)
Oops? What is "oops?" It is something you say to a person you bump or after you fart in public...not when you are a slob and drop lettuce on someone...oops...please.
By this time, I had had enough.
I turned to him and was...rude.
I said, "Do you know me? Are we friends?"
Beast Man was taken aback. "No, I don't think so."
"I didn't think so either, because only my friends can spill lettuce on my shoe and think it is funny. I don't know you. I don't want to ever know you. I just want to pay my bill. Is that okay with you?"
The clerk at the counter smiled (I could tell he was very glad someone said something, because he either lacked the skill or courage to say it himself). I turned away from Beast Man and gave the clerk my phone number. As I was doing so, Big Boy gathered the parts of his dismembered sandwich and left...not bothering to pick the lettuce off my boot.
My point in telling this story is....
At some point we all do stupid and annoying shit. Sometimes we go overboard and it bugs the hell out others. It is only when someone is rude...blunt...do we begin to realize how awful our actions or non-actions are. We realize how foolish we were.
In reality, we should thank rude people. If it wasn't for them...we would end up just like Beast Man. When our mother chided us on how rude is was to talk with a mouth full of food or chew with your mouth closed....was she rude...or right?
As comfortable as he was, chomping away and passing the time with strangers, it was clearly not the first time he had done this...but I bet he won't do it again.
I did Beast Man a favor and if you ever come into a place and see me sitting at a counter eating my supper...please, be rude to me too.