Coming from ME...hahaha... I prefer to say exactly what's on my mind, because as the famous quote goes:

"How will a person know what your thinking, if you don't tell them?..."

(And this goes for both directions...) If you are in the presence of a person who just rubs you the wrong way, just leaving them where they stand, without a word exchanged, is useless, for they will just return, and annoy you again!

If, by chance, the person isn't a bad person, so-to-speak, and you just don't want to deal with them anymore, it's all you have to do, is simply say,

"Hey, listen, you and I are on totally different wave lengths, and I have better things to do, besides sit here and listen to your gibberish jaw-rattling... Ciao!" ...and that's it!

BUT, if you must be polite, the best thing to do is just calmly say,

"I...don't...like...you".

My biggest pet-peeve is people who like to run their mouths with their brains out of gear... MOST annoying! ("Just SHUT UP ALREADY!") In this case, just tell them to shut up because they make no sense...

Another example, is the one who knows all, has done everything, and is the best at everything, and owns nothing but the best of all products... and likes to make it known... For these people, look at them oddly, like you have NO idea what they are talking about, and simply just roll your eyes, and WALK AWAY... They might get offended, but if you don't "fancy" the person to begin with, then what's the problem?

Now, for someone who is drunk and being loud and obnoxious, the best thing to do in this situation, if the person is in your home, simply ask them to leave. If they don't leave without a scene, then unleash hell on their asses! There is nothing worse than having to deal with a drunk on a rampage... Tell them exactly what you think, as their brains are foggy, and they can't comprehend reality... they think they are bullet-proof, until they trip over the dog, trying to get to the toilet! No worries here, they probably won't remember tomorrow anyway...

Sometimes, when you first meet a person, you get these "sirens" going off in your head, and there is just something about the person that you don't like... In this situation, stay away from them... your conscience shouldn't be ignored... If they bother you repeatedly, then you will have no choice, but to tell them that you can't stand being around them, that there are higher powers at work here steering you clear of this person...

All-in-all, it is best to be honest, (putting all sarcasm aside) If you can't rid an annoying person just by being polite, then you MUST make it personal, and tell them what you think... Otherwise, they will never know, and they will keep bothering you. Honestly, being able to speak your mind kind of gives you confidance, and makes your chest puff up a bit. It's not an issue of being polite... it's an issue of whether you are in control of your own life, or not...

~Don't let anyone make you feel small...

~Don't let people look down on you...

~DON'T live your life to please everyone except you... TAKE CHARGE!

If YOU can't say what's on your mind... WHO WILL???