You're so quirky

Used in a very sarcastic way usually online.
Sometimes used in a bitter way but most people use this term to confront someone's 'wannabe' and or 'try-hard' behaviour, usually said towards people that are trying way too hard to seem different and unique.

Someone who might have an individuality complex and or feeling as though they are superior because e.g. they listen to an 'underground' band when the band is obviously high status.

Basically said to a person who is extremely inauthentic trying to seem as authentic as possible.

*Someone gloating about how they drank 3 sips of vodka* *Someone noticing* 'Wow you're so quirky arent you!!'

etc.