To be "Pithled": When among a large group of people, one may find that everyone's acting strangely, unusually and/or differently, for no apparent reason. Thus, confusion and a feeling of non-hostile alienation are experienced by that individual, or sometimes minority group.
Mostly the cause of being pithled is unknown, making it worse. However, some known examples include: An in-joke of which everyone bar you is aware of, being the only sober person at a party, some kind of mass behaviour with no obvious cause e.g. everyone you pass on the street wearing flip-flops on a rainy day without a reason such as a charity event or something, and being much more high than you thought you were, provoking people to wonder why you are acting strangely and in-turn they themselves might act out of character e.g. watching you and laughing or keeping their distance. (Also being high can increase the effects of being pithled.)