It was a pretty standard takeoff in my new, beloved Bonanza. I rotated nicely, gear up and made my turn to the north where I would cross the Runway 34 centerline before incoming jet traffic. Looking ahead, even at 1,500 feet agl the haze looked solid, but as I said 5 miles of light haze will still look the same as 1 mile of solid haze. I was climbing to the northwest as I watched the approach end of Runway 16 dart in and out from behind some low-lying haze. For a few seconds on and off, the ground disappeared behind a small puff of haze and clouds. Then, just white. At 2,000 feet agl, I waited a few seconds for the ground to reappear so I could turn around and get back on the ground. I would not be filling up with fuel. That moment didn't come. Suddenly, I was approaching 2,500 feet agl, the floor of O'Hare's airspace, and punching through solid clouds at 120 knots. IFR pilots fly in this stuff without batting an eye. VFR pilots in this unexpected situation and flying alone don't. It is scary.