Hmm... this is a hard one. Illinois has numerous counties I don't really care for, but don't really hate. I guess it'd have to be Morgan County. I hate its shape and I once got lost in "downtown" Jacksonville, so there. But outside Chicago, county lines really don't matter... it's all corn and soybeans.
Oh I also hate the shape of Tazewell County too.
You clearly haven't been around your own state much if you think it's "all corn and soybeans," but I highly doubt it's worth it to argue about this with you.
Anyway, the objectively worst county in Illinois is Alexander. That shouldn't even be debatable. It's hell on Earth.
Nah nah I'm not one of those Upstaters who thinks there's nothing down there. I went to EIU, so I've lived downstate. And honestly, I prefer it to Chicagoland. But in general terms, it's mostly corn and soybeans. I went to Springfield a few weeks ago and really enjoyed it. I like Peoria. I've had some awesome times in Quincy. I love the Quad Cities. Galena is awesome. I think you read too much into what I meant.
Need I remind you, I grew up in a small farming town, so I'm not some suburbanite saying this. I've spent my fair share in rural Illinois.
Cairo, Illinois is a terrible town, so Alexander should win for that.