A classic epigram:

Etiquette is the cheapest and most profitable substance in the world. -Napoleon Hill

In interpersonal communication, the more thoughtful manners, the safer. -[English] Thomas Carlyle

Knowledge makes people gentle, while communication makes people perfect. -[America] Joe Fuller

The real civilization lies in that everyone leaves his due rights to others-ingersoll

If you accumulate steps, you can't reach a thousand miles, and if you don't accumulate small streams, you can't make rivers and seas. -Xunzi