In almost all cases, strong personality traits which are considered good, when taken to the extreme can be very bad. For example, being persistent can lead to someone being insistent. When you cross that line with a person it is not going to turn out well for you--in the long term.
From a Puget Sound Business Journal article on Brad Tilden, CEO for Alaska Air Group, there was this comment about good employees, "...and have the right kind of ambition, which is focused on the company and not themselves."
I think you can be ambitious and still put others first. Being ambitious is a good thing when it is not all about you. When I was in the Army and attending Infantry Officer Candidate School there was this motto printed on the stair risers in my end of the barracks. It said, "Mission, Men, Me." I adopted that as a personal credo for my military career--always putting the mission first, men second and myself last.
What I observed later in my career was that if you are putting the mission first, then are you not also putting yourself before your men? Since, if the mission is successful, then you are successful. More self-reflection made me wonder where "family" fit into the above mix of priorities.
I've blogged on this quote before, but I think it is right on the mark, "The presidency does not make the man, it reveals the man." This video clip is a great visual of who's number one.