(ethics) A wrongful action is not a morally appropriate way to correct or cancel a previous wrongful action.

One should not unappreciatively question or inspect a gift too closely.

Alternative form of don't give up your day job

Alternative spelling of don't cry over spilt milk

Alternative form of you can't judge a book by its cover

(aphorism, humorous) The stereotypical man does not do things that are considered effeminate.

(idiomatic, vulgar) One should not cause trouble in a place, group, or situation in which one regularly finds oneself, as it will likely backfire

Used to introduce one's opinion about something to which offence could be taken

There are consequences to not wearing a condom on one's penis

Don't criticise something before having experienced it.