For those not in the know, Chicago has different driving rules.
1) Any space greater than my vehicle plus 6 inches is big enough. People don't cut you off they are just using the space. You will also find that Chicagoans are very good at paralel parking.
2) Posted speed limits are suggestions or averages. If I was moving at 30 under the limit last time, (during rush-hour) I can go 30 over today.
3) Passing on the right is OK, especially if it is an out of state driver that doesn't know the rules.
I learned to drive in Chicago, and people used to think I was aggressive. If they could see me now....