8. Joan Redfern
Joan Redfern had an interesting relationship with the Time Lord. She was introduced in the Series 3 two-parter, Human Nature/The Family of Blood, and fell in love with the Doctor's human alter-ego, John Smith, rather than the Doctor himself. In fact, there were even suggestions of marriage between the two when John Smith saw the life he could have if he didn't turn back into the Doctor. However, even when hiding as a human the Doctor attracts trouble. The Family of Blood tracked him to the village bringing destruction and death to the life that Joan had always known. Even in the face of the Family's love of devastation and determination to get what they wanted she didn't want to see Smith embrace his Gallifreyan origins. He did, though, and the Doctor offered Joan the chance to travel with him. She turned him down, angrily, on the grounds that he was no longer the person she loved despite having the same face, and that he indirectly caused the deaths of all those the Family of Blood killed by choosing where to hide on a whim. Which suggests that the Doctor's adventures sometimes have consequences that put even those who were close to him off.