People are going to scream about price gouging.
Congress will pass a law or two relating to the matter.
Those email forwards about how we’ll break the back of the oil companies if we all boycott one or if we all don’t buy gas on a particular day will be sent around even more.
More people will consider fuel-efficient cars.
Many people will consider alternate (public) transportation, or vacations that don’t rely so much on driving.
People will scream and complain, but pay the $4 per gallon.