We May Never Know The Real Reason
The question is, what exactly caused the tension between the two of them? It would appear that we are unlikely to ever learn the true reason why Kevin Smith and Bruce Willis had a falling out, but we do know that Kevin has been left with a lot of feelings toward his co-star. In an episode of Marc Maron’s podcast, the director admitted as much, describing the experience as “soul-crushing.”
That wasn’t the end of it. Kevin continued to add in his book that he believed he was going to work with the “happy-go-lucky charmer” he had worked with in the past but was met with “the unhappiest, most bitter, and meanest” version of Bruce he had ever seen. Kevin described this version of Bruce as “the unhappiest, most bitter, and meanest” version of Bruce he had ever seen. It should come as no great surprise that Kevin and Bruce have not collaborated together since that time.