The Fifth Doctor was portrayed by Peter Davison from 1981 to 1984. After the longevity and popularity of the prior incarnation, the writers were going for a big contrast. This Doctor was less brash, more vulnerable, and more comfortable with letting randomness pull him along (rather than having to put his finger in every pie, as it were). And, to paraphrase one of his later incarnations, for some reason he liked to wear a decorative vegetable...
Despite the Fifth Doctor's casual nature and whimsical attire, the plots of his time grew a bit more serious. One human companion was killed in action, and another proved to be a secret agent with murderous intent. The end of the Fifth Doctor's reign came when he sacrificed himself to save still another companion. I haven't watched any of this Doctor's episodes, but I did see him come back through time to meet the Tenth in a special short made for charity.
"There's always something to look at if you open your eyes!"
"You may disguise your features but you can never disguise your intent."
The Fifth Doctor is a SAGITTARIUS. I'm sure I must be making the shoe fit somehow, but the list of characteristics seems to match up yet again... "optimistic, jovial, honest, but also a bit tactless, blindly optimistic, and reckless." The Fifth Doctor seemed to try first to turn enemies into friends, and only fight them as a last resort. His idealistic emphasis on making the world a better place also seems to mesh with the Sagittarius penchant for pondering the meaning of life and valuing freedom and truth.
The New Year's Resolution for the sometimes flighty Sagittarius is to think about cooling your jets once in a while. Instead of looking ahead to the next, greener pasture, have a look at what's around you right now. As with some of the other signs, such a remedy can also feed into the other aspects of this personality type, such as philosophical contemplation.
[See the introduction for more about sources and motivations for this series of posts.]