What is it with drivers in the Chicago area?

I really need someone to explain to me why people driving in Chicago and the suburbs (mainly the suburbs) do the following:

1. When approaching an intersection that the light is green for them they hit their breaks
2. When they see a car stopped in the lane next to them they hit their breaks or stop

Idiot drivers are one of my biggest pet peeves and these are the behaviors I see the most while driving around. I don’t get it!? 

Something else I don’t understand is people that go to a mall and circle the parking lot until they find the closest possible space. Then they walk around the mall for HOURS. What was the point of looking for a close spot? To save steps for walking the mall? I was at Old Orchard on Tuesday afternoon for an Apple training session. When I came out, another driver followed me to my car and waited until I pulled out of my space. A car two spots away from me (further from the shops) pulled out first. The car waiting for me saw them pull out and STILL waited another minute for me to pull out, then took my spot. I don’t get it!!!