What kinds of tactics are commonly used to psyche out opponents?

I haven't been to a tournament or chess club.  I haven't played OTB for years.  Someone played psychological warfare on me to win a game recently in my local town at a pizza joint a few months ago, which I've described here before.

But I'm wondering what are common kinds of ways players at tournaments try to psyche out the OTB opponents?  And what are the more extreme ways seen?

And when does it go, or has it gone far enough to disqualify the player?

Walk around when ur position is bad or equal to show contempt for your opponent.Kick him in the leg a couple times and apologize as if you dont mean it,Deny everything he says if he calls the arbiter.Look at his moves with disgust to show him how crappy you think his moves are.Call the arbiter if he offers you a draw and accuse him of offering draws repeatedly.Hit his pieces hard while capturing.Stare at him like a psycho.Ill update the list later when i remember a few more.

I usually place my gun near the board and start twitching a lot.

lol

I met this guy once who mastered the art of planting an idea in your head.That's right folks if you ever watched the movie "Inception",this guy is a master of mind trickery.While playing,he is constantly talking about mundane things,sometimes philosphical things.Somehow he can hypnotise his opponent to play a certain move.I know its weird but this is street chess.

Don't people ever tell him to STFU.

Opponents who wear hats bother me. Especially the Indiana Jones hats. I sit down opposite one of those and I feel like resigning.

have a feed of garlic prior to the game and and smile at your opponent often 

Emmanuel Lasker was a master of psychology and mind games he knew Aaron Nimzovitch hated cigarette and cigar smoke so he took out of one of his cigars from his pocket before his game began and put it on the table as if he were going to light it at any moment this had the intended affect of upsetting Nimzovitch who complained to the tournament arbiter who told him Lasker didn't do anything wrong he didn't light it Nimzovitch replied  "He is threatening to smoke, and as an old player you must know that the threat is stronger than the execution"

Playing the opening really quickly is always nice to do. I've usually played with a 5-second delay, and when you're on move 8 with 2:00 still remaining on your clock, and your opponent's used 10 minutes, that has to count for something.

Of course you have to know your theory quite well, and know your responses to certain non-theoretical moves too.

I know a guy who's seventeen, looks like he's growing a beard if he hasn't shaved that morning, weighs over 240 pounds, plays very agressively, and is built like a bear.  Whenever he puts the other person in check, he slams the piece down hard enough to bounce the table and shouts out, "Check!"  In all seriousness, he almost made an opponent's younger sibling cry once.

If you win through intimidation and a subtle/implicit threat of violence, that's just bullshit.  That's not chess.  What's the difference between that and bringing a weapon and telling someone to resign or get hurt?  

He plays very well; it's just that his manerisms distract the other person.  He's a realy nice guy who wouldn't hurt anything.  One you're used to it, he stops.  Sometimes he just gets excited and slams the piece unintentionally.

Well, the theatrics and any sort of weird threatening behavior should be disqualifying.    Of course it could be really subtle and subjective.  Very difficult line to draw.  That doesn't mean that some lines can't be drawn.  

I call the line at when it's distracting other players at different boards, but when it's the last game being played or nobody is distracted by it, I say it's acceptable, if only borderline.

Just stare at your opponent non stop. If it's your move and you are decent at blindfold keep staring at them and run over ideas in your head. They will lose their nerve pretty quickly.

Yes, there can be OTB, correspondance chess, blitz, bullet, and the treacherous 'nerves' variation, where it's all about intimidation and whether you can stand up to the implicit threat of violence, sexual pressure, strange odors, or the promise of wealth, fame, job position, etc...

I go to bathroom during the game and return with a big fake mustache. I lick it slowly with a creepy smile on my face every time my opponent touches his pieces. When in difficult position I grab my man tit and lean over the chessboard so it looks like we're analyzing the postion together.

Crossdressing, serial killing, cannibalism, incest, heresy, etc.

Once, I was playing in a tournament and my opponent [who I think had eaten onions or something] frequently exhaled on my thinks at an angle that bounced off the board and into my face. He was actually quite masterful at it.