13. The First Doctor
"One day I shall come back. Yes, I shall come back. Until then, there must be no regrets, no tears, no anxieties. Just go forward in all your beliefs and prove to me that I am not mistaken in mine." - Flashpoint
The First Doctor changed enormously over the course of Bill Hartnell's tenure. Indeed, the Doctor started off as a crotchety, irritable old man, often more at home on his own than galavanting around with others. Perhaps it's this change of heart(s) over the course of the first Doctor's run that makes his farewell speech to Susan all the more powerful. This short moment of utter poeticism from the Doctor is one of the first real glimpses at the man the Doctor would eventually become. The wording is simple - the Doctor displays his sadness for having to leave his beloved granddaughter behind, yet he is also hopeful for the life she will lead. Never before had the Doctor seemed more warm and likeable than in this heartwarming moment in which fans saw just how much the Doctor can care. Fans often refer to this moment as a benchmark for how beautiful the words of a Time Lord can be. It also set the bar for companion exits. Some may even argue that this scene is the definitive moment of the First Doctor's time aboard the TARDIS as the first time fans saw who the Doctor really is underneath.