Yes, actually. Crashes, for example, can't be predicted via Waze and periodically f* up your commute in an epic way. And they happen very quickly and the effects ripple through the system equally quickly.
One other thing. If you get on at 22nd street, headed north on 294, past the Cermack toll (and 290/Roosevelt ramps), you have no exit available for about 8 miles. So, you're committed. And, once you've made it that far, you might as well stick it out, because it'll open up to 80-90 mph as soon as you get past the Touhy toll about 2 miles away.
Yup, happened again this morning for me. Same spot as last week. North bound accident between the Ohare Oasis & the 90/190 exit ramps. 2 lanes blocked. 40 minute estimate from when I left at 8am turned into 70 minutes by the time I arrived at work.
In addition to what drewbug stated: I check traffic before I leave. If I'm lucky, there's a stated 10 minute delay due to a single accident. By the time I get to where the accident was, there's been 3 more. In my 25 mile commute, it's common that I see at least 4 accidents each way. See my other comment, by the time you're on the highway, due to the routes, it's a waste to reroute, mostly due to lack of off ramps.