I had a friend who had a car with different keys for the door and the ignition, and he lost the door key. I fashioned a coat-hanger wire into a tool to slide down the window and unlock the door.

By the time he got a replacement key, I was literally faster at opening the door with my tool than he was with his key — once you get the knack of it...

(of course the tool was much more clumsy to carry around than a key, and 2 seconds vs 3 isn't enough to care)