Quite a story. I'm glad you didn't 'get' to kick the idiot's mirror, while feeling the source of your motivation quite strongly, given the circumstances
. I'd hate to see you made the legal 'bad guy'. It's easy to prove a kicked mirror, where the buzzing you described is virtually impossible to prove unless it leaves a mark or is caught on video.
When it comes to pro-actively addressing this type of problem, have you considered or do you use a rear-view mirror? Though I just broke 2600 miles on my bike a couple of days ago, they're largely MUP miles. I'm still a noob when it comes to cycling with cars, and still find it intimidating, though less so than when I took my first baby steps last season.
One thing that's really helped me to build that confidence is using a rear-view mirror. Mine is glasses-mounted, but they come in plenty of other types. It takes practice to get your eye to focus and interpret the image properly, but it's worth it to be able to see when automotive traffic is coming and whether they've gotten over or not before you find out the hard way. Another somewhat surprising benefit is knowing when other cyclists who choose not to warn you about it are about to pass.
Stay safe out there.