Forgive me, but I happen to be one of those courteous drivers. The closer you get to my rear bumper the more likely we are to meet under less than pleasant circumstances (and I don't mean I am going to go after you). Besides how can you expect me to go faster than the car ahead of me?
Have you ever noticed that in business some people have that same sense of urgency? They're in a hurry to get something done and they're too impatient to recognize that others in front of them (upon whom they depend to achieve your goals) are not moving as fast as themselves? What do they have to gain from pushing others along? Everyone has an agenda- is one persons agenda more important than another?
Sure, there are those instances where someone else has agreed to support you and for whatever reason they are not living up to their side of the deal. Other than that, it's important to have realistic expectations. It's like the impatient driver on the road- go around if you must or just accept the fact that the world does not revolve around you.
And keep this in mind… The only way you are going to push me is to push me away! Is that what you really wanted to do?