Motor morons

Something I don't understand is what people are doing when they get into their vehicles, start the engine, even turn on their headlights, then sit there for several minutes, doing nothing, with the motor running, while I am waiting for the parking space.

You finally pull up beside one of these sluggards to ask if they are going to vacate the space, but the drivers usually keep their windows up and their eyes averted and pretend like they don't know you are there. Then, when you give up and move on to look for another space, they pull out behind you and drive away. Duh!