Waiting

As most people know I am not a very patient person, or at least I didn't used to be very patient. I think patience is one of the biggest things I have learned from Jeremy. So now that I know I have become a more patient person, why do I still have trouble waiting?? Whether it be waiting at the Doctor's office, waiting for an e mail from a professor, or waiting for my water to heat for tea, I still have trouble waiting. Why is it that waiting for something we really want, or need is so difficult??