Now, read this document to learn about English Proverbs. Birds of a feather flock together . A new broom sweeps clean . Don't count your chickens before they're hatched . Too many cooks spoil the broth .
Fools rush in where angels fear to tread .
When in Rome, do as the Romans do . Looking at the evidence in The Bank of English, the striking thing is that the initial phrases are used rather more frequently than the full proverbs. It is as if our knowledge of the full proverb acts as a kind of shared cultural background which doesn't need to be expressed in communications between native speakers. The initial phrase is enough to trigger the full meaning. You felt something special between them that left you out.