Open or closed garage door?

I'm sure this has a pretty big variance on what neighborhood we're talking about.

Where i live in Idaho, in the suburbs outside of Boise, it's crazy how many people just leave the garage doors open all day, everyday. I see it when I'm driving through the neighborhood and most of the time they close them at night, but during the daytime it's the same people that have the garage door open with bicycles, motorcycles, skis, all sorts of toys and they just sit there all day with a door open. Been like this for the last 10 years. I always thought it was kind of odd.

So this question is for the people who do it, why? Why not just close it?