This is a central theme in Mick Napier`s book Improvise - Scene from the inside out . The idea is the improvisors fear the consequences of their own actions (or the actions of their characters) and as a result, freeze, or stick to safe-but-boring actions and scenes. Napier urges us to fuck our fear, and just do something, anything, and see where it leads us while improvising.
Napier`s Axiom: Just becasue something follows the rules does not mean it will work --- Mick Napier