F.I.B. : The Derogatory Nickname Cheeseheads Call Illinoisans

I'm from Milwaukee but I've never shared the hatred Wisconsin people have for Illinois people. When I was a kid I loved going to Six Flags in Gurnee, IL and, as a comedy fan, had nothing bur reference for the iconic comedians that came from Chicago's Second City (John Belushi, Bill Murray, Gilda Radner, Harold Ramis, Christ Farley, Dan Castellaneta, Jeff Garland, etc., etc., etc.).
But the hatred is real...SO real that Wisconsin folks call Illinois folks "F.I.B.s", which does't stand for "friendly Illinois buddies."
I'm F.I.B. now and I think I have a good theory on why Wisconsin hates its neighbor-to-the-south so much.