Haha I've also angled my side mirror out of my eyes, which incidentally is back towards the car behind me. I of course angle it back if I need to change lanes, but it's such an annoying thing I have to do just to see the road ahead of me.

At this point I put full blame on car manufacturers and lack of government regulation and enforcement. Lights will keep getting brighter because lights are getting brighter. It's a death spiral.

My 2017 Ford Fusion has an auto-dimming driver side mirror. I hate driving a car at night without this.

My rear view mirror does this, I wish my side mirrors did too. Although recently I've noticed some cars headlights can even pierce my rear view mirror's polarized dimming. It never used to be a problem in the past. I've seen the difference when drivers turn their high beams on and off. It always did a great job against driver's brights including large trucks. But occasionally there's now a vehicle with the light of a thousand suns that is too bright for the auto-dimming.

The older manual rear view mirrors worked much better in my opinion.

That indicates the low beams are incorrectly adjusted.

The problem is most drivers dont care.

Why isn't this flagged during the MOT?

Not all states have inspection, and those that do don't necessarily include an alignment check.

I've half jokingly told my wife I'm going to make a parabolic mirror for her to aim back at such drivers.

… or a steerable corner-cube array or retroreflector prism. Steerable in that it needs to slightly redirect its reflection to above the light source—to the windshield area of the offending vehicle—rather than exactly back to the light source.

When I get incorrectly flashed I force my high beams on and keep them on, FYI. Don't do it.

Maybe this ought to indicate to you that your low beams are blinding other drivers dangerously.

If you have OEM headlights, I can understand your frustration - neither you nor the other driver has control over that. I think this is what OP posted this whole thread about.

If, however, you've installed third-party LED headlights, then you're sort of on the hook for this.

I'd add that whoever it was that 'incorrectly' flashed you is long gone by the time you're leaving the highs on and blinding everyone in your path. That's aggressive and uncalled for.

I only do it if no one is behind the flasher; I thought was obvious. And I have OEM headlights.