Quoted By:
Hank believes something always tragic happens to him whenever he starts getting cocky and believing his own hype, ever since the fateful day he broke his leg during the finals. This happened again when he carried the torch for the olympics. This curse will eventually lead to his demise. What would send his ego through the roof? It's simple: Propane. There are reasons in the grand scheme of things as to why Hank hasn't been given the promotion he deserves or why he can't just run Strickland Propane himself. Just look at how many times Buck cheated death with so many of those heart attacks. It's because the time hasn't come yet. When Mr. Strickland dies, Hank will take his place. The same mistake he made in the past will return and Hank, despite running the company better than before, will think he's king of the hill. That's when everything goes to hell. There's no doubt he will die because of this, but how? Most likely from injury or accident. Looking at Hank's lifestyle and diet, he could suffer the same fate as Buck and die of an infarction. An ironic turn of events dealing with propane could be a devastating explosion. It was Hank's biggest fear, after all, so you could call it a foreshadowing.
>How does it affect the rest of the show?
Remember when Hank found out he had no health insurance and isolated himself from friends and family? They make it pretty obvious everyone is hopeless without him. Dale, Bill, and Boomhaur could've burned down Rainy Street if Hank hadn't come to the rescue, and it's implied Peggy and Luanne get in trouble with the law. If Hank dies, you can be sure chaos will erupt among the rest of the cast, probably start with something asinine Dale does. Just look at what happened when Hank went along with one of his conspiracies for once, it led to a tank destroying property.
TL;DR: Hank is cursed and will die from either a heart attack or some Final Destination shit, which will lead to the fall of Arlen.