"laziness"

Hello /sci/,
Could you explain to me why people are willing to go out of their way "to be lazy".
Examples:
  Walking an extra 20 feet to the automatic door instead of pushing open the other door.
  Waiting an additional 5 minutes instead of going up a flight of stairs.
I'm sure you've observed others. Is it just a habit people get into? Has there ever been a study into this.

>>120
Hold it there Kodak! Nice try, but I made that up! I really don't know where you are, but you sure are not in my own mind, I can insure you of that! I would have detected your approach within thousands of miles! I would need a address to visit where you are on the astral plane! I need to at least know where I am going, or else I would end up inside a wall, or something like that and it would end my trip real quick!