Additionally, it is generally the case that we humans often behave worse than usual when we think we can get away with it. For example, people say much harsher things in online forums than in one-on-one situations. Sitting "safely" behind the wheel of a car can bring out the worst in us because we know that we will probably get away with bad behavior. If you've also had a bad day or have been irritated over time by cyclists or other drivers, it can feel good to "finally get back at them."