I have always wondered about which of the Doctor's companions was his personal favorite. It might be awkward for you to name a particular character here, so I decided to remind you of a particular moment as the Doctor with my favorite companion, and see what the Doctor was thinking at the time.
You have often stated that you simply played yourself as Doctor Who. Given that premise, and what it might mean in how you shape your character, step back into your role as the Doctor, and describe what you were thinking and feeling in the episode Hand of Fear, when Sarah Jane said goodbye.
PS: Thank you so much for interacting with us this way. What a grand thing for you to do!