One of my favorite Ethel Merman stories invoves Jerry Orbach. During one scene in the "Annie Get Your Gun" revival in 1966 {aka "Granny Get Your Gun"), Jerry was upstage of Merman, who of course, played everything to the audience. One night Merman noticed a new reaction from the audience, one she hadn't expected. Next night, it happened again.
Perplexed, Merman told the stage manager to summon Jerry to her dressing room. "Orbach," she said, "you're DOING something during that scene. What are you doing?"
"Nothing, Miss Merman," Jerry replied.
"Don't lie to me, Orbach. I know you're doing SOMETHING. Tell me what you're doing."
"Honest, Miss Merman," the actor replied. "I'm not doing anything. I'm just reacting."
"Aha!" Merman said triumphantly. "I knew it was SOMETHING. Listen kid, I'll make a deal with you: You don't react to ME, and I won't react to you. Deal?"
With that, Jerry Orbach shook Merman's hand. And he never reacted to her again.