We have met the enemy and he is us. You can never rely on what the other driver will do. Think back to all the mistakes you've made while driving over the years. Think ahead to the ones you know you will make in the future. All the other drivers are just like us! Don't trust them! While you are driving, keep a wary eye on the other guy and leave yourself plenty of room. Anticipate the mistakes he might make and be ready for them. Eventually, he will! Because he's just like us! When you are driving on "autopilot," you have turned control of your vehicle over to those other drivers - you are at their mercy. Their fate is your fate.
If you are too trusting, you are relying on that other driver for your safety. Is he worthy of that trust? Every few seconds, some drivers in this country find out this is a poor bet. Maybe some of those other drivers are returning from a beer festival! Maybe they just lost a job, or worse, a loved one. The other driver might be an 11-year-old who found Dad's keys. Approach driving with the idea that every other driver is an unpredictable menace and out to get you. Most collisions occur when the "other guy" does something we don't expect, or when we do something they don't expect.
If you accept that everyone makes driving errors, the next step is to drive with a wary attitude. Be careful of approaching red lights, because you know a light by itself never stopped anyone. Watch out for folks getting ready to pull out from parking beside the road. Look for gaps in lines of traffic which might be the result of someone pausing to let another vehicle cross in front of them. (I've personally witnessed three or four collisions in the past ten years that happened just this way). There are others: failure to signal a lane change or turn, or tailgating someone when they are poking along because they need to make a turn—a turn they suddenly WILL make when they see it at the last second. You can think of dozens of others. Be alert to the possibilities and have a strategy in mind for dealing with them.