Can a Buddhist be ambitious?

Over the last few months I've distanced myself from my sangha and from Buddhism in general. I still meditate but no longer identify as a Buddhist. One of the things I've noticed is the return of some old ambitions or longer term desires if you like. I don't think they are negative in fact they could have quite positive outcomes though I do recognise that they are driven by a restlessless sort of dissatisfaction. In the light of my recent experience it makes me wonder if Buddhism necessarily dampens down people's ambitions? Is it possible to be ambitious (in any sense) and a Buddhist or are the two things mutually exclusive. For a Buddhist is ambition a negative thing?