The closest I get to confronting drivers is the damn fools (I.E. half of them), that insist on stopping on crosswalks when they have a red light. Some of the MUPS I use use crosswalks. They can completely block the ability to get up on the the other side. I usually glare and they get the message. Of course, many give me a 1-finger salute just for giving them the stick eye. Because they know they're in the wrong. A few times I've muttered rather loudly something like "Hey, f-wad nice job" or similar, to then notice they had their window down and certainly heard me. Doesn't bother me a bit.
Just last week, I had a guy pass me on a frontage road where he could have simply moved into the other lane, instead, they chose to pass about 5-6 feet away. My Varia radar camera clocked him at 97 MPH. I gave a finger (which I've done maybe 1-2 other times on the bike), though I doubt they even looked back let alone saw in the fraction of a second before they were out of sight.
I've shouted at maybe two other drivers who at first shouted at me the very original "Get the F off the road".
But in general, I try to avoid responding. Most drivers are making small innocent mistakes that I've made myself while driving (see the above pulling onto a crosswalk for example). If a driver cares, they usually will know they screwed up and there's nothing to be gained confronting them, at least aggressively. The types that just don't give a s&*t, aren't going to consider anything you have to say.
And, I've made my share of bonehead mistakes riding. So, I try to keep in mind that none of us are perfect.