Remember the lovestruck Derpy YouTube videos? The doctor fell for A TREE! Literally! I think that Octavia is jealous about the whole Derpy + Doctor thing because she does not have a boy pony friend. I think they should not date (Hence, Octavia and the Doctor), because it would not work or be pretty for Derpy. Outside of the YouTube videos, however, the Doctor is not in love with Derpy, which makes no sense to me. It should be constant- Derpy in love with the Doctor.