Laughter is the best medicine - unless you're diabetic, then insulin comes pretty high on the list.
In discussing the process with the actors, I made it clear to them that they could improvise but that the sum total of their improvisation needed to impart certain plot points, and schematic material.
When I got out of high school, I thought, I'll take a year or two off and play the clubs, get this out of my system, and then go to med school.