咱们合作多年,你再这么客气就太见外了。Zánmen hézuò duōnián, nǐ zài zhème kèqi jiù tài jiànwài le.We have worked together for years; if you are still this polite, you are being far too formal.
都是自家人,别这么见外。Dōu shì zìjiā rén, bié zhème jiànwài.We're all family, so don't stand on ceremony.
朋友帮了你,你还要给钱,是不是太见外了?Péngyou bāng le nǐ, nǐ hái yào gěi qián, shì bu shì tài jiànwài le?A friend helped you and you still want to pay him; isn't that too formal?