The term rubberneck describes what you do when you can't help staring at something. People tend to rubberneck when they're passing a car accident on the highway.
You might rubberneck at a waiter who drops a huge tray full of glasses. Tourists are sometimes accused of stopping to rubberneck at unfamiliar sights as well. Rubberneck was first used in 1897, from the idea that nosy or curious people turn their heads for a closer look as if their necks are made of rubber.