Kindness
From Tardis Wiki, the free Doctor Who reference
The Twelfth Doctor told Alit that she was just being kind when she showed Bill Potts her reflection. He also told Missy and the Saxon Master that he was helping the Mondasians due to it being a kind thing. (TV: The Doctor Falls)
In a speech to the Thirteenth Doctor, the Twelfth Doctor told them to be kind. (TV: Twice Upon a Time)