Having been a driver for 18 years and having driven numerous cars in that timeframe, there are some things that I’ve learned over the years.  Here are a few of them:

1. A part that costs less than $30 will give out when you least suspect it and gladly cause another $1000 in damage when it does.
2. While individual drivers may be intelligent, a group of cars driving together is only as smart as its weakest link.
3. Never underestimate any driver’s ability or likelihood to do something unexpected or stupid (including when you are a passenger).
4. Nobody likes getting pulled over and most people don’t likely shift their habits much or for long due to being stopped.  That aside, if you get stopped, be polite and respectful.  If you want to fight it, fight the system, not the cop – the former often works, the latter almost always doesn’t.
5. Don’t assume, no matter how competent the mechanic, that small details won’t get overlooked (e.g., forgetting to tighten the drain plug for the transmission, forgetting to tighten the lug nuts after hand tightening).  Check their work – especially if it is your work.

Bonus:  If you are driving down a 25 degree include on a country road at over 60mph and come upon someone going slower than you’d prefer – especially if you are towing a camper with a sofa tied to it – don’t try to tap the guy’s bumper to get him to let you past.  Conversely, if you are the slow guy in front, get the hell out of the way.