Being Filmed while Driving

This morning on my commute to work a car matched my pace with their window down, while the driver pointed a camera at me to film me. This occurred on 23 Northbound towards the Plymouth Rd. exit. Has anyone else experienced anything like this in Ann Arbor? I can provide details on the car if needed. The behavior seemed very erratic and intimidating. I’m not sure what I could have done to make this guy so mad, there are so many unstable people out there in the world.