What was Sean Penn’s biggest mistake?
https://www.quora.com/What-was-Sean-Penn-s-biggest-mistake/answer/Jon-Mixon-1
He never sought serious therapy for his anger issues - Sean Penn's behavior would have earned him several stints in prison if he wasn't famous. He doesn't, however, seem to have actually done anything his issues and so his career bogged down.share
He should have gotten into film production decades ago - It was clear by the early 1990s that Penn was not going to remain a leading actor for many years into the future. He should have created his own production company and made money behind the scenes. He didn't until much later, and now he's just “one of the crowd".
He seems to have never developed a sense for picking financially successful films - Sean Penn's career is littered with great films and terrible ones, the majority being failures at the box office. If he had learned how to pick a hit 35-40 years ago, things would have gone much better.
His marriage to Madonna - Besides apparently fueling some of his more violent impulses, it did nothing for him personally or professionally. They don't even seem to stay in contact and he certainly could have benefited from her wealth and her connections many times over the last 30 years, excluding her testimony during his libel suit. Basically, he wasted time and effort on a relationship that seems to have hobbled his career.
He never got a franchise - It was clear that Penn was never going to be an A-list box office topping star. He needed to develop a franchise (or two) where he could crank out a quick film every now and then to keep people's attention to him if or when his other projects didn't hit. He's been in the business for more than 40 years, and he should have realized that. He apparently has not.