(informal) Do not give in to petty problems; don't worry about insignificant matters.

Persistence is important in the pursuit of success.

One should not carry out an action if they are unwilling to handle the consequences.

(humorous) A term often used after a person claims to have no expertise in a topic of discussion, but still wants to contribute a comment.

Alternative form of if it ain't broke, don't fix it

Alternative form of better the devil you know than the devil you don't know

Used other than figuratively or idiomatically: see don't, tell, me. / (idiomatic) Used to introduce a guess at a fact or situation, as if forestalling the other speaker's utterance.

The frustrations with a system or activity should be blamed on its weaknesses, rather than on individuals who operate within it.

Indicates that the speaker does not want to take something that is being offered.

I don't have any money