The HID are High Intensity Discharge headlights, essentially it's like driving during the day only it's at night and it pisses a lot of people of that are driving at you (best invention ever for driving back home to Wyoming on 2 lane roads).
Our HIDs were so bright (when they were new) that a state trooper pulled us over and told us to dim them. They were already on dim. So, I had to drive through the next 30 miles of his patrol area with fog lamps only. I went to the dealership and had them print out an inspection ticket stating the lights are factory set, unadjustable, and within legal limits of output and angle. Apparently the trooper and I have different ideas of what is safe. I think everyone should be able to see at night and he thinks we should mount lamps onto our "metal" covered wagons. The lights have gotten slightly dimmer over time and are not quite as obnoxious to other drivers now as they were when they were new.
I've noticed the same thing from other drivers after I added the HID to my Challenger- and they are not even the same temp (lower output) as the factory ones. The setup had a bug in the harness to where a relay would buzz on high beam & there was no difference in output. After it was fixed, I usually give a courtesy flash to those that high beam flash me so they can see I wasn't on high beam. Ran into a similar thing with halogens when they first came out.