The actors playing the Doctor always try to contribute something new to the part, but no one did more of that than Tom Baker. The first two Doctors, Hartnell and Troughton were pretty serious about their job, i.e. saving the earth or the universe. Pertwee, the third Doctor, was an improvement, there were things he seemed to enjoy, but even when he was driving his little yellow model-T around he was usually racing to the rescue.
Tom was different. Most of the whimsical aspects of the fourth Doctor such as the scarf, and always having a bag of jelly babies in your pocket, were Baker's contributions, not the writers. Tom's Doctor also attempted to do things just because they were enjoyable, like punting down the river or TARDISing to a vacation spot, True, the vacations were always interrupted by armies of evil aliens attacking, but at least he gave it a try.
Baker was born January 20, 1934. He left school at 15 to become a novice monk and remained in the monastic life for six years, but left after losing his faith, and did his National Service in the Royal Army Medical Corps. At the same time he took up acting, at first as a hobby. He became the fourth doctor after he was spotted in "The Golden Voyage of Sinbad" and stayed for a record seven years.