Willis and his kid gradually coming to the realization that Willis has never been injured and that they can't put enough weight on the rack to find out where the limit of his strength is was a really cool way to portray his super powers. He's gone through his whole life just thinking he's lucky and strong, because why would a normal person ever try to lift a car over their head or stand in front of a machine gun? And Jackson as Mr. Glass manages to tick all the boxes for a classic comic book villain while still having a unique and interesting motivation and a sympathetic backstory that does nothing to justify his monstrous actions.