Something originally designed as a survival mechanism. Now used by people with long legs to taunt people, everyone else to catch some form of public transport. of course the driver will purposefully wait untill you are 2 feet away from the door before buggering off.
"Run Forest, run!!!
"Oh, cheers for wait- Oi!!!"
Lanky guy: catch me if you can!
Short guy:all right (suspicious loading sound)