I only think of positive outcomes

Make a list some evening of the disasters you have fully rehearsed. The diagnosis. The redundancy. The conversation that would end a friendship. The presentation that would go so badly you would have to leave the industry.

Most of them never came. The ones that did arrived in a shape you had not drafted, and you handled them anyway, without the rehearsal being any use at all. That is a long record of forecasts and almost no hit rate, which is worth weighing before you commission the next one.