8. Tegan Jovanka (Resurrection Of The Daleks)
Tegan, played by Janet Fielding, was a companion to the fourth and fifth Doctors. Uniquely she posed as a role model for future companions particulary those of recent Doctors. At one point in Time-Flight she gets dropped off back in her home city of London for a year, only to be picked up again in the next adventure, Arc of Infinity. It certainly sounds very reminiscent of the Amy Pond story, where she would be returned home at the end of adventures. In fact, it even happens with the current companion, Clara Oswald. But at the time of Tegan, this was quite new. Tegan's departure is essentially a long brought on stress-filled exit. She had seen another companion die more on him later and went through an emotional rollercoaster in her final adventure with our time lord. In the end, the character simply couldn't take it and left the TARDIS for the final time. It was a dark, grown-up exit we could all appreciate, and it felt like an honest exit for the longest-lasting companion of the Peter Davison era.