Restraint is a key factor in all the art that really moves me.
Example: music. If a guitar player goes nuts for an entire song and pays no attention to dynamics, I don’t care how technically good he is or how much he shreds, my emotions are dead.
It’s not just art. When a person tries too hard to make a good first impression and smothers an organic conversation with self-assertion, I start looking for an exit.
Underdo it. Leave people wanting more. When you leave it all on the table, you take away the suspense and people lose all reason to pay attention.