Since it's not exactly rocket science or even difficult to do it right, why not do it right? I can guarantee you, if they are high enough to cause one person to flash their high beams at you, they are bothering more than just one person. It isn't like the old days when people would flash you in a heartbeat if your lights seemed too high; these days people don't have enough hands to even use turn signals on a regular basis, much less use the flash feature (one hand for the coffee cup, one hand for the phone, one forearm or knee to steer, etc.).
Now that I'm an official "old fart", misaligned headlights on oncoming vehicles really bother my eyes. Add to that the extra glare caused by the various HID and LED lights being installed on more and more vehicles these days, and it becomes a problem even for younger folks. I try my best to keep my lights aimed so I'm not blinding anyone, not just because I'm such a nice guy (

), but also because that person you just blinded may swerve into your lane just as often as the other way.
JMHO - Jerry