Hermes

“But this is touching, Severus,” said Dumbledore seriously. “Have you grown to care for the boy, after all?”
“For him?” shouted Snape. “Expecto Patronum!”
From the tip of his wand burst the silver doe. She landed on the office floor, bounded once across the office, and soared out of the window. Dumbledore watched her fly away, and as her silvery glow faded he turned back to Snape, and his eyes were full of tears.
“After all this time?”
“Always,” said Snape.”
― J.K. Rowling, Harry Potter and the Deathly Hallows

“Mr. Moony presents his compliments to Professor Snape, and begs him to keep his abnormally large nose out of other people's business.
Mr. Prongs agrees with Mr. Moony, and would like to add that Professor Snape is an ugly git.
Mr. Padfoot would like to register his astonishment that an idiot like that ever became a professor.
Mr. Wormtail bids Professor Snape good day, and advises him to wash his hair, the slimeball.”
― J.K. Rowling, Harry Potter and the Prisoner of Azkaban

“Dumbledore watched her fly away, and as her silvery glow faded he turned back to Snape, and his eyes were full of tears.
"After all this time?"
"Always," said Snape.”
― J.K. Rowling, Harry Potter and the Deathly Hallows

“Snape's patronus was a doe,' said Harry, 'the same as my mother's because he loved her for nearly all of his life, from when they were children.”
― J.K. Rowling, Harry Potter and the Deathly Hallows