Improv principle #1

This is post #1 in a series of principles I thought might be useful, mostly taken from the Internet, perhaps with my own spin on it as well.

1. yes, AND...

If your partner in a scene says, "Look, it's a train," say, "Yes, and it's coming this way." Use what you are given and add to it. Don't try to push the scene toward your own pre-conceived ideas, or it will die a slow and ugly death. Listen to your partners, take what they offer and build on it.