People connect at a basic intuitive i.e. "gut" level and thus i consider the following character traits as the most important;

1) Sincerity - Sincere about their job, putting in the work reqd. and taking care of the "team".

2) Honesty - No unnecessary political games and being honest about one's limitations and strengths i.e. what they can and cannot do.

3) Trustworthy - A man of his word and understanding vis-a-vis deadlines, features and requirements. Somebody who can be depended upon to always be there when things get sticky.