Cars

I say this in the least creepy and voyeuristic way possible: I like to watch people in their cars. Mostly at stoplights. Not only does it help pass the time, it alleviates my road rage because I can just laugh at the dickhead that just cut me off. Most people seem to neglect that all the windows in their cars, not only the front and back windshields, are... well, clear.

Let's break down the most common...
-Zoning out and staring straight ahead into space
-Looking at self in rearview mirror (mostly women)
-Singing and bobbing head to music
-Talking on the phone without a headset while looking around for cops
-Picking nose covertly.. or some not so covertly
-Spilling water on face from water bottle (just one old lady, her face was priceless)