Sometimes, someone will wish to talk to you when you do not wish to talk to them. My solution is to be faultlessly polite, evasive, and condescending. A guide for this purpose follows:
1. Answer questions concisely and pointlessly. Reply to the letter of a question rather than the spirit, which will be to make you reveal information about yourself. Volunteer nothing, and provide no hooks on which they can hang another question. If your ambusher is forced continually to jump from topic to topic, they will eventually become too embarrassed to continue.
2. Do not ask any questions of your own. This will convey that you do not care about the answers, or by extension any personal information they might volunteer. Attempt to give the impression that they are not worth your time, and that you are bored. This should work in conjunction with unfailing politeness to make it clear that you are humoring them. You may also wish to evince indifference toward things they profess to enjoy, even if you enjoy them yourself.
3. In improvisational exercises, there is a rule that says you must always reply “yes, and–” to statements and questions, because “no, actually–” stops the scene cold. In this case, the latter is what you want, so employ denials and minor corrections liberally. The more pedantically exact your mien, the more superior you will seem. Feel free to experiment with other techniques such as using better diction and grammar than the other party, having perfect posture, and removing emotion from your face and voice. The less human you are, the more difficult it is to talk to you.
4. Cultivate plausible deniability. Give the other party no opportunity to fault you for rudeness or incorrect opinions (the latter is most easily accomplished by expressing no opinions). Some unsavory conversational partners will attempt to engage you in an argument in order to provoke you into disclosing emotion or personal beliefs; be indifferent. Use the “it’s a free country” defense if necessary. Remember that you do not care how wrong this person’s opinions are because you do not want to associate with them.
5. If all else fails, recruit a friend to discuss something that only the two of you understand and/or care about. Alternately, speak in a foreign language. This can be done via text message if no friends are in physical proximity.
Some of these may also work if you’re being interrogated, but the threat of physical violence makes it pretty difficult to be condescending. If you fear for your safety, I wouldn’t recommend trying to seem superior.