Growing up, I was a fast walker. My grandfather had installed in me the idea that being on time meant being there before I was expected, and for whatever reason, I really took that to heart. When I got into middle school I was all but running through the halls to make the most efficient use of the six minutes between classes to exchange books from the locker and sometimes traverse the whole of the building in the process. Once I got into high school, things were no different except we had seven minutes, and there I was taught to not just walk, but march. If my grandfather's insistence hadn't been enough, those six years of school would have done it to me anyway.
Throughout most of my adult life this has also been the case for me. I've been one of the first people to work (and many times among the last as well). I get to church early. I get to appointments early. Pretty much, if someone is expecting me to be somewhere, I wasn't going to have them waiting on me if that was at all possible. Perhaps as an extension of this mindset, this often meant that if someone was expecting something of me, they would get it and likely a bit more. But it's not over-achieving if it is only meeting my own goal.