Al povero mancano tante cose, all'avaro tutte.
The poor man is lacking many things, the greedy man all.
To me that's a great proverb. It shows that when you're poor you could still be content but when you're greedy, even if you're rich it's never enough, there's always something you feel you're lacking.
Grammatically it's a great way to understand the verb "mancare" (to miss or be lacking). In Italian the "misser" is the indirect object and the thing missed is the subject.
So English: I (subject) miss her (object).
Italian: Lei mi manca. ("She is missing to me.") The object in English (her, the thing missed) becomes the subject in Italian (lei). And the subject in English (I, the "misser") becomes the indirect object (mi). Confusing right!