Bruce Willis is awesome at waking up hungover, getting shot at and asking someone to get his ex-wife on the phone. His movies succeed when he remembers that.
"In trouble with the old lady" is the only way Bruce Willis knows to be married.
In fact it has been argued, most notably by us right now, that Bruce Willis is the only person who could have played the child psychiatrist in The Sixth Sense. In the first scene, the character's happily married and getting ready to bone his wife when he's shot.
If it had been anyone else, we would have immediately wondered why his wife was refusing to look at him or even answer his questions in every seen after that. With Bruce Willis, we just clucked our tongues and thought, "Just like Holly. I wonder what he did this time."
Before Die Hard revealed his true purpose, Bruce Willis was known as a comedy actor (thanks to Moonlighting). Like Americans blessing the queen, or applying leeches to plague victims, this is the sort of ridiculous historical fact we know to be true but just can't process with our modern brains. In Die Hard, we learned how to convert metric to kickass (one American Willis = two dozen European terrorists), and found that a vest on Bruce functions like body armor on regular humans. If he ever actually wore something bulletproof we'd have to surrender control of Earth. There's no way we could stop him.
Everyone in the world knew that Die Hard had revealed the true function of the Bruce Willis... except Bruce Willis. Imagine Mozart had played the piano for five minutes, then decided to take a job getting his fingers caught in garbage disposals. Now imagine Bruce Willis playing the part of a wisecracking unborn child in Look Who's Talking, which can only be described as goodmouth--the absolute opposite of badass. He did it again after Die Hard 2, creating the Law of Conservation of Willis Badassery : For every kickass movie he must do something so offensively terrible the net increase in awesome is zero.
This pattern could have ruined his career if he hadn't crammed a lifetime's supply of terrible into Death Becomes Her--a movie so abysmally bad he could re-release Die Hard every year for the rest of the century and still have done more harm than good.
Hudson Hawk was so terrible it destroyed Tristar Pictures, which was bought out by Sony after losing 48-million dollars. There were three reasons for the failure:
Mixed in with other actors Bruce Willis can get away with more than normal. In Pulp Fiction he became the only actor for whom desperately seeking an object that had been rammed up another man's ass is a heroic story of honor and loyalty. He is in fact the only character for whom the backstory, motivation and villain all involve things being rammed up asses outside of Indiana Johnson: Riders of the Lost Crack. In Armageddon he was a rogue oil driller--we've abandoned the concept of words making sense eight words into the first sentence--launched on a shuttle to save Earth by nuking space. The fact that it not only happened but was awesome reveals facts about the human mind that most are not ready to handle, yet.