What's the rush

Went to Pretoria today, not my favourite place to visit but sometimes don't have a choice, as was the case today. You all may think I have a mental problem but for some unexplainable reason I do not exceed the speed limits. If you choose to speed, then it is your choice, but for myself I am not prepared to accept responsibility for injuring or killing another road user, and yes that does include animals that happen to be on the same road as myself.
The road I use is a country one, single lane and with the usual compliment of pot holes dotted here and there along the way. It is quite busy but usually the traffic manages to keep up to the allotted 80 or 100km.
Today the road was busy, but nothing exceptional, traffic was however building up a bit as there was a large truck battling to keep up to the speed limit of 100km. Suddenly some inconsiderate road user (not the words I used at the time) put his foot down on the peddle, swerved off the road and proceeded to overtake everyone on the left side (remember in South Africa we drive on the left), thus throwing up dirt and rocks on all the vehicles he passed.
One of the rocks happened to hit my windscreen and crack it rather badly, I do not know if I was the only one who suffered damage, but on stopping as soon as I could (without causing another mishap) to assess the damage, I lost my cell phone just to really make my day.
Was his rush so great that he could not stay on the tar road? Did he just not care about other road users?
Surely if one drives a vehicle one should also consider other road users but as we so often see these days no one ever wants to be anything but first in line, pushing, shoving and bad manners are the rule of the road and a lot of other things it seems.
Where does honest courtesy start and why doesn't anyone seem to use it any more.
Most of all what made him more important than any one else on that country road. I hope he arrived at his destination safely and did not have to put up with the loutish behaviour he himself displayed.