I was that way when I was younger, I love it now, but for me King of the Hill was too "serious" or realistic, it's less absurd than other similar shows like the Simpsons, the plots are usually more like something that could happen to real people, and the comedy style is drier/more subtle. I have friends who never really got into it when it was newer because of that.

Also having family from the southern/midwest US there are aspects of the characters that tie into cultural tropes that if you aren't familiar with wouldn't appreciate as much, whereas Simpsons and Futurama have less specific references to US culture more based on Hollywood and political history of the US. For example my grandma who was born in Nebraska and has lived around the south most her life loves King of the Hill after getting into it not too long ago and isn't so much into The Simpsons.

King of the Hill is a lot more steeped in US culture. For example, Dale Gribble is pretty much an archetypal right-wing conspiracy nut, to quote one of the writers. The right-wing conspiracy nut is a particular US character, and his version is the 90s version that is pro-gun, obsessed with UFOs, thinks the government is spying on him, and gets away with paying taxes to stick it to the Man. They got politicized through Ruby Ridge and Waco. If you're familiar with the X-Files or Deus Ex, they are a good intro into the mindspace of the average conspiracy theorist from the 90s albeit with far less racism.

Modern right-wing conspiracy theorist is Qanon/Alex Jones bullshit. It's a pretty different vibe from the 90s version that Dale represents. His modern counterpart is like sovereign citizens.