Bat Vader said:
I want everyone who is saying the OP is in the wrong or rude to answer me a question. Why is it ok for someone to try and force a conversation onto someone else but it isn't ok for someone to not want to have said conversation?
Because OP is being rude. He's literally ignoring the content of what they say, or any potential reason they could be talking to him with "Please don't talk to me", and the way in which OP describes using this phrase merits concern. The specifics of having an "anti conversation phrase" and considering shutting down the interaction "mission accomplished" should raise an eyebrow, it's not socially well adjusted behaviour, and not recognising the rudeness adds to that sense. Which has led to numerous aspersions on their maturity, because this is a textbook immature thing to say. It's the sort of thing I'd do when I was between the ages of 13 and 17 and was terribly socially adjusted.
And part of this concern is for the OP as well, because it turns out that this perspective on conversation is great for leaving one truly lonely, which is a great risk factor for all sorts of shit, but also because it stunts one's emotional and social development, and can prevent one from finding success in employment, maintaining friendships and relationships, and generally doing the things an adult needs to do to get by. Again, I have done this. I have been this, I have seen this, and if I had the chance, I'd go back in time and smack my younger self in the face. For me, it was a response to how I was treated. I was regularly the target of bullying, by pretty much everyone, so I went, fuck it, I'm out. Not an experience uncommon around these parts I'm sure. There were people I wanted to talk to, people I liked romantically, people I thought were interesting or cool, but I never learned how to make myself interesting to them, because I closed myself off to everybody and hid behind my books and schoolwork. I decided that if society was going to bully me, then I wasn't going to engage with it. But the truth is, not everyone was going to pick on me, some could of been, and some became, good friends, and that is important to have, but more importantly, making friends is a skill every adult requires. And, to be blunt, your lack of social skills makes you a target. Your old friends leave, they die, and they get sick of your misanthropic crazy bullshit and stop replying to your messages (Some habits are hard to break). Every social interaction is that chance to improve yourself. I told myself I was an introvert, a sociopath, autism spectrum (And fuck, I may be, but I'm crazy enough without asking for a diagnosis for that), or that I just didn't like people. My role-models were House, and other assholes who thought they were the smartest person in the room, and treated everyone with disrespect. Ironically, had I been smarter, I'd see exactly how this sort of character was designed to appeal to me, by refusing to criticize my refusal to develop myself and be a decent human being, and instead tolerate my shittiness, and say that people will still need you, because you're just that smart. That's why you suck at social things. Because smart. You don't have time for that. For a long time I was the smartest person in the room, then I was the second smartest person in the room, and didn't that just burst my smug little bubble. Worse, the prick was friendly, he was well adjusted. The fucker was nice. And he wanted to be friends with me, and I just wanted to hate him for beating me. I never realised I was the bad guy. I never realised that I now wanted to mistreat people and dislike people, the very thing that had hurt me to begin with. I could have actually been smart, and teamed up with him and got smarter together, but I was too busy pretending I was Sherlock before Benedict Cumberbatch began convincing people that a lack of ability to read basic social cues, and refusal to consider others was either sexy or intelligent. I was lying. I was lying to myself, and for all my supposed smarts, I couldn't pick up on it. I was afraid. I was afraid of what people would do to me, I was afraid of what they had already done. I'd been beaten, assaulted, sexually harassed, ostracised, teased, mocked, the rumour mills, the fucking works. Had I had more friends, had I developed, I might have escaped a lot of that. I did not. The people who mistreated me took that away from me. They took away that development, that adjustment, those years of social interaction. One of them recently got back in contact with me to apologise. They can go to hell. They took a lot there. When I finally realised I actually needed people, that I wanted to go to parties, to have LANs, to talk about videogames with, to drink, to fall in love, to date, to talk to people, I realised I actually needed some of those skills, and I had to teach myself the basics. That was a lot of trial and error, and a lot of failure. And, oddly enough, a lot of trying to say nice things to strangers, or start brief miniature conversations. I'm still not there yet. I'll never be the most charismatic, I'll always feel awkward, but now I can honestly say that I can be a leader, I can talk to a stranger if I have to, that I can ask for help, or try to make new friends. I had to overcome what was really fear of social interaction, of others.
You can say you don't care about other people, their conversation, their opinion, their souls, whatever. If that's really the case, then why do you answer at all? Why would you give a fuck if you're rude? I'll tell you what, as I've said before in this thread: I am often rude. I am a rude person. I am being rude here and now. All of my responses have been rude, and that's in part because I recognise this pattern of behaviour. If you really didn't care, you wouldn't care about being rude. If you really didn't care about conversation, you'd feel no impetus to reply, and you'd have no problem with people considering you rude. If you truly dislike social interaction, people, society, then why would you care which side of the social contract you fall on, how your behaviour is held? What does it matter if they think you rude, you're never going to talk to them, their opinion will never effect you, because of how you choose to cut yourself off. It is typically dishonest, and hiding, and it will likely make your life harder, whilst being just unfortunate for any old ladies with the misfortune to encounter you.
If the people who actually talk to each other, and make idle conversation, the supposed "Extroverts", are the one's engaging in social interaction, then it is their attributes that govern rude. Those who refuse to interact will always be rude, because while you can consider the people starting conversations rude on your own, you actually need to interact as part of the social organism to have any sort of group consensus of rude.
And I know this won't sink in, because I've had this conversation with my younger brother, and my friend's older brother. They've essentially stopped bathing, washing clothes, and live in squalors, because outside of one or two drug addicted losers they play MOBAs with, they have no friends. I'm terrified that my younger brother will encounter drugs, because he's perfectly set to become isolated like that. Eventually, when people they know stop hanging out with them, because they don't brush their teeth, which are yellowing, and their hair is a different shade from grease, and they smell, they grow more miserable. My friend's brother is almost 30 and he's moved back into his parents basement. He has almost no friends that aren't his brothers, and apart from me, most of those have fallen away. I haven't seen him in almost a year, because he's almost never out and about. He's depressed, and desperate for a romantic partner, but he's incapable of understanding that it's his lack of social skills and hygiene that prevent this. And I know that everyone will find a reason to say that they're not like that, that they're the exception. If that's really the case, then it's possible that you may need psychological help, if you really think that you cannot socially interact, or that you don't need others. They can help you find techniques to feel less put upon by the old ladies of the world.
But to answer your question more specifically: Starting up a conversation is an imposition on someone. Whether it's rude or not depends on how you do it. The bogan woman who wanted free pizza from me tonight initiated conversation by asking "Hey, you, give me a free pizza". So she got a rude reply "Not until you get me a pack of smokes". And the mildness of the rudeness was only because I was working. She knew that shouting at a minimum wage employee who wasn't free to call her a fuckhead, waste of space derro **** was inappropriate and impolite, she did it because of that. She's a cowardly bully, a waste of space. A rude, unpleasant individual. The lady who explained that she took a while getting to the door because her legs fell asleep? We had a lovely conversation about bad circulation and how much of a nuisance it is. Took about 30 seconds on my delivery, put a smile on her face, and let me know that I'd reached out and touched another person in some small way. This is what is truly meant by appreciating the little things.
You can be impolite starting up a conversation, and you can be polite declining one. You just need to show respect and consideration for another person, and understand basic social cues. But I really would suggest actually engaging with it, because either way, it's probably going to be gone in a minute. It really doesn't take up much of your time, and it does have tangible benefits. You can walk away at any time.
There are polite ways to disengage from conversation, be it complete honesty as BiscuitTrouser suggests, white lies, or actually having something that you need to do. If you politely disengage, and someone persists, they can be being rude. But again, it depends on what they're doing, what their aim is. The way you and OP talk, it's as if you're thinking that it's only the "extroverts" (And I hate this label, and the converse is equally dreadful. The most common, and least useful self-diagnosis floating around, bar, "I am a wolf trapped inside a boy's body", is "I am an introvert" and here is a meme I found on how to "care for me" etc.) who need conversation. I'm not great socially, and I often desire human company and conversation. It takes a bit to screw up the courage to talk to a stranger, or ask for help when I need it. For all you know, it's someone who actually has a serious problem they need help with, or it's some anxious, lonely soul like most of us, trying to make a fleeting human contact to remind ourselves that we're not entirely alone. It's not about making things about you, often it's about them. Some of the people I have the greatest respect and appreciation for started conversations with me, and that was because they saw something in me. Whether it was good, or bad, whether they wanted to get to know me or help me, they saw something, and expressed and interest, and sometimes, you do need it. People don't only talk to you because they want to share how great they are. These people are boors. They are rude. People often do it because they suspect you may be great, and they want to experience that. Or that they think you might not be feeling your best, and that you might need some help.