No artist is perfect and even the greats will have their off days. That is an undeniable fact.
That being said, the number of lackluster films from talented filmmakers is still inexplicably large. Of course, there are many reasons why directors turn out bad movies. The exhaustion of having to put out so many films, being stuck with underwhelming material, studio interference or even running out of good ideas has put a damper on many a directing career, but many of these failures still don't make sense.
After all, Christopher Nolan has done 10 diverse, risky films and all of them went well. Hayao Miyazaki has directed 11 films without a dud. Stanley Kubrick never made a bad film despite making 13 films across a range of genres. Akira Kurosawa never messed up and he directed 31 films over half a century.
Given the talent all of these following directors have, their failures are always confusing, and they are responsible for some of the most disappointing films in recent memory. In some cases, it feels like a close friend had betrayed you...