Too often, a bicyclist gets mad at a cager (a car driver) when they have an unfortunate interaction on the road. Usually the driver speeds away, all the way up to the next red light; in a few minutes, the bicyclist catches up to the cager, gets their attention (sometimes by tapping the vehicle), and gestures with their middle finger to signal their opinion of the driver.
This is generally a dangerous situation, because (1) drivers object to the middle finger, and (2) the car weighs 3500 pounds and the bike weighs 18 pounds.
A new concept in bicycling gloves promises to change all that; the new Good Day Gloves by Pryme carry a positive, life-affirming message on the middle finger, to help improve the cager-cyclist relationship.
Somewhat related: "Give them the finger", Danny Kaye, in The Inspector General