For guaranteed suicide in Chicago ... ask for ketchup on your hot dog
I've never been to Chicago but a friend of mine just went there and while he went wandering around, he asked me to research as much as I could about the city to see what he should or shouldn't do.
Every person I've ever talked to from Chicago says deep dish is a tourist thing. I have to agree with the larger consensus that it's not that good. Not awful by any means but it's not good enough for how difficult it is to eat without making a big mess.