Both Moffat and Davies are well-known for the darker, sadder themes in their writing. Neither writer is afraid to write a heartbreakingly sad episode, and both have written tense, eerily dark stories for Doctor Who. Steven Moffat doesn't so much build an episode with sadness, but he does shock his audience with the final reveal that everyone won't live happily ever after ('The Angels Take Manhattan', 'A Good Man Goes to War'). Davies alternately sets up the tragedy to come a lot clearer by foreshadowing it, like when Ten knows he's going to die, and Rose narrates the opening scene of 'Doomsday'. Whilst both writers have delivered tragedy though, Moffat is more of a "happy ending" writer. RTD isn't afraid to end a series in complete despair for the Doctor, and is willing to make him lose everything. Moffat alternately, always ends on something sweet.
