Not exactly sure what the deal was. I was behind one exiting a parking lot and then making the same right turn. Driver was really slow. Maybe 20 MPH in a 25 and later I'd estimate 25 in a 40. So I was a little bit mischievous and did some mild weaving in the 25 street before making the right turn. He's making the turn real slow, and I make the right and later pass him on his left to accelerate past him. I never made eye contact or even drove terribly aggressively. Then I notice the bird. Dude was maybe late 20s/early 30s and not grandpa. As I went past he was still driving really slow. Couldn't figure out what the deal was.