Assuming the speed limit was 70, I'd say they were already going fast enough at 75. In reality the left lane is supposed to be reserved for cars traveling at the maximum posted speed limit or passing. If they were at 75 as you say and the speed limit was 70 as I assume, they really did nothing wrong. However you passing in the right hand lane as you simply had to go faster was a douche move. Running late? Leave earlier next time. But I completely agree with the stop with the cell phone and drive, shit eats me up when I see people doing it and driving like crap while at it.