King of the Hill is known for its deadpan humor and equally as taciturn protagonist, Hank Hill. While Hank isn't exactly the most emotional individual, he's exactly the opposite of his coldhearted curmudgeon of a father, Cotton. Arrogant, hateful and reveling in the fact the killed fifty men during World War 2, Cotton's disdain for the world at large is only second to his dislike for Hank himself.
There are numerous possibilities for why Cotton can't stand Hank or his ex-wife Tilly, but a Reddit post has recently illustrated how a two-part episode perfectly explains the bitterness in Cotton's heart. According to theory, the Colonel's hatred of his first son and ex-wife stem from his lost love in Japan.
COTTON'S TIME IN JAPAN
In the episode "Returning Japanese," Cotton informs Hank that during World War 2, he had been treated by and fallen in love with a Japanese nurse named Michiko. Though they both clearly felt for each other, Cotton's being shipped back to the U.S.prematurely ended their relationship. Unbeknownst to Cotton, he had conceived a child with Michiko, and it was only upon returning to Japan to reunite with her decades later did he realize this fact.
The theory puts forth the idea that it was his inability to be with Michiko that made Cotton so hateful and resentful toward Tilly, and later, Hank. Having gotten Tilly pregnant, he would be unable to simply return to the country whenever he wished. Kept from being going back to the one woman that he likely ever truly loved, he would logically see his new responsibilities by way of a wife and child as a burden. It makes matters worse that he never seemed to have even a fraction of the affection that he had for Michiko for Tilly. Now trapped in two relationships that he never truly wanted, Cotton became angry not only at his new family but the world at large.
COTTON CAN'T STAND ANYBODY
The theory is somewhat sound given Cotton's treatment of Michiko compared to literally every other female character in the show. It's easily dismantled, however, given that Cotton's treatment of Hank and his mother isn't too much worse than how he treats everyone else. The world at large is disrespected by Cotton, who revels in his misanthropic behavior. Even neighbors of Hank's like Dale, who he sometimes gets along with, are occasional victims of his ire. In fact, some of the only characters who are consistently treated well by Cotton are his second son G.H. (Good Hank) and grandson Bobby.
Cotton's rather odd affection for Bobby runs counter to this theory of deep hatred for Hank. Bobby, in spite of being even less rugged and masculine than Hank in comparison to Cotton, doesn't receive even a fraction of the torture that Cotton gives Hank. On top of that, after returning to Japan and reconciling the events of his life, Cotton doesn't suddenly become more appreciative of Hank or even simply less combative toward Hank. To be fair, this may be due to seeing the son that he had with Michiko and resenting Hank even more because of it. Ironically, he is a caring father toward G.H., even though he has no real connection to his second wife outside of a clearly purely sexual one. If he was angry over being tied to a woman besides Michiko, it wouldn't make sense for him to choose to remarry, let alone be a much better father with his second child.
As sound as the theory does seem at points, it seems that, in the end, Cotton Hill's irrational antagonism toward almost everything in his life is just that. If anything more, it's simply the culmination of several different disappointments, and not just one.