Quiet In Line
People who have been in the military stand in line quietly and do not make a ruckus. This comes from basic training. Soldiers stand in line and in controlled silence before they enter the mess hall or while they wait for orders. In civilian life, they do the same while waiting for the bus or the ATM.
Checking Your Car
In the military, the key to being safe is discipline. Prior to going out on a mission, soldiers must check the vehicle they are using to make sure it is prepared as well as safe, be it a fighter jet, a helicopter, or an APC or armored personnel carrier. Even after discharge, this habit persists and they check their own private vehicle.