One of Clara’s echoes met Luke Rattigan and was friendly to him. She influenced him to follow his dreams and be a little bit of a better person. When Ten beamed up to the Sontaran ship, Luke thought of the girl who had been his only real friend and decided to do something that would make her proud.
In “The Doctor Dances”, when Nancy admits to the child she’s his mother, she says “I’m so, so sorry.” This inspired the Doctor to say the same thing in his tenth regeneration. submitted by numberjonnyfive
Rory suffers from delusions and multiple personality disorder. He was never The Last Centurion, he never waited for Amy as she was more of an alternate personality, The Doctor humored Rory’s fantasies and found that it made adventures more exciting.