In improv and theatre sports, one of the first concepts you learn is "Yes, and" -- the idea that you accept what your scene partner is offering, or building, and you built on it with them (rather than rejecting their work and/or trying to control the scene). This is the heart of good improv.
The opposite of "Yes, and" is "No (/but), or blocking, where you reject what your partner is doing and obliterate their work. It stops a scene dead (and makes others not want to work with you). 1/n