(informal) It is impossible to always succeed; failure or disappointment is inevitable from time to time.

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.

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.

There is nothing someone can do to evade something.

(idiomatic, impolite) Said to dismiss what the interlocutor is saying.

The wisest and the most experienced cannot be easily deceived.

A person who has talent, resolve, or moral strength will eventually succeed despite having been overlooked, injured, or defeated.