It's called Courtesy people

Pet Peeve. Situation: You're driving and the car next to you is trying to merge, blinker and all. Then out of the courtesy of your heart you decide to slow down to let the other car over into your lane. In the process of them merging you kind both have this understanding of the gratitude the other has done for the other. Such as slight wave in the rear-view mirror. Anything? Well it bugs me so badly. This morning I did this such action, being a good person and letting a car merge in front of me. I gave them the "You're welcome," wave and got NOTHING in return. Thus leaving me awkwardly in my car, like waving to someone in the hallway in high school when they were really waving to the person behind you. It's somewhat embarrassing sometimes. All I'm asking for is a wave....is that so much to ask for?