I thought that was just the common case in the books as to why they did. It can be other emotions than love. Harry thought that Tonks had changed hers to a dog because she felt like she was responsible for Sirius' death. At least I thought he did.
I don't think Lily's partronus is a doe, well it doesn't say. but Snapes the one whos partronus is a doe...........
posted over a year ago
Actually, it does say. Harry says to Voldemort, "You never saw Snape cast a patronus, did you, Riddle? [...] Snape's patronus was a doe, the same as my mother's, because he loved her for nearly all of his life, from the time they were children." [pg 740]
James is a stag because Lily is a doe. Lily made it clear that she had no interest whatsoever in James while they were at school, but James was always in love with her and probably chose his Animagus form to be a stag to reflect his love.
