What I call "acting over the shoulder" is a typical symptom of bad acting. The actor’s lines are like orphans. Abandoned. They don't connect. There is no will to influence. They sail past their intended target, flying over their partner’s shoulder to expire somewhere in the wings of the theatre. Actors should instead speak to their partners, trying to change them. They should feel their own words as active sense organs, exploring the contours of a partner’s personality.
