Exit/Entrance

Because in a fire most people will surge towards whatever exit they can find, most, if not all, buildings' entrances swing outward. Meaning, don't expect to have to push the door to enter a building.

Holding doors

When entering/exiting a building, always hold the door for you as you walk through it. If someone's behind you and you let the door half-close in their face you will look like a jerk.

Traffic tickets

Signing a ticket given by the police isn't an admission of guilt but is instead simply signifying you've received the citation.

Hot Coals Disposal

If you're going to have a barbecue at a tailgate (or any other event), make sure you have a plan/place to dispose of the hot coals after you're done using them.

Brushing in the morning

Brushing your teeth in the morning's purpose is not to clean your mouth after breakfast, but instead to rid your mouth of the bacterium that have grown in your mouth in the course of the prior night's sleep.

Lights on

While you may be able to see the road perfectly fine, turning on your headlights while driving in the evening, in a tunnel, or in a parking garage is not so that you will be able to see more clearly; rather, it's so that other drivers will be able to see you.