"I'll waste more gas turning off my car and then turning it on again instead of leaving my car to idle."
FALSE: You don't expend more gasoline turning your car on than you would idling. This is simply not true.
-Click & Clack

"Idling is good for my engine."
FALSE: It actually gums up your engine making it operate less efficiently when idling. Driving is the best thing to do for your vehicle because it moves fluids through the engine
-Ricky Forgeon, Mechanic

"It will take a long time to warm up the engine if I turn it off."
FALSE: Actually, after 30 seconds your engine is hot
-Ricky Forgeon, Mechanic

"It will damage my starter if I keep turning it on and off."
FALSE: Modern cars are designed to handle multiple restarts throughout a day and won't hurt it at all. Many cars even include options to have your car automatically shut off rather than idle.
-Ricky Forgeon, Mechanic