One time Robin Williams was being interviewed long ago and doing that magic comedic improv thing that he does. The interviewer asked how he makes that stuff up so quickly. He said, “I don’t. I’ve already thought of it before and get to say it now.”
Eminem studied the dictionary to learn as many words as he could and then practiced and practiced.
Interrogators role-play and practice to get good at what they do. Hostage negotiators do the same because they shouldn’t be practicing when it matters.
I listen to the Office Ladies podcast where Jenna Fisher and Angela Kinsey break down episodes of The Office. It is amazing how often people think these great lines are improv. Almost all of them were written by a team of writers who have to figure out the story and structure.
Avoiding practice is just slowing your growth and making it so you practice on the unsuspecting clients. Get past your fear, your ego or whatever is holding you back. Get better faster.