A person will continue to display the inherent qualities of the place from which they grew up, or spent a significant amount of, in.

You cannot fit a large object or amount in a smaller container.

(idiomatic, figuratively) It is not possible to make reliable judgments about things or people by considering external appearances alone.

(colloquial, rhetorical question) directed jestingly or mockingly at someone who has received surprising information, ridiculing the situation

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

You can't have it both ways.

If your adversaries are stronger than you, it is better to join their side.

(informal, humorous) Your mission or task; what you must do.

(rhetorical question, colloquial, childish) Assertion that an insult made by the party to whom the phrase is directed is actually true of that party, and not of the person using the phrase. Usually considered to be a playground taunt.

Alternative form of you don't dip your pen in company ink