The Beginnings of Road Rage

Recently, I have been developing a lower and lower tolerance on the road. This is really just for one particular thing... entering the highway. The on-ramp to the highway gives you enough time to accelerate to the posted speed limit of 100km/hr. Why is it, then, that I see so many people entering the highway at 70km/hr?!?!?!?!? Seriously? I'm a courteous driver, so I slow down to let these people on. But f.f.s, step on it a little, would you? I'm running late for work sometimes.