Severitus in canon is the most depressing concept ever, like, hello? Harry probably spent so many nights tossing and turning, thinking about all the potential. He grieved what no one else really did, grieved potential. He probably searched for him in others, he had so many questions. He thought of how the person who had been so cruel had actually had a reason, and how even though his face was a collage of Severus' failures and attacks, his worst memories and the worst outcome for him, he cared. How he was one of the only people who truly valued his life and health. Severus probably felt failure in his last moments, how he couldn't even protect him fully. He never got to see that he survived, he had died staring at his failures, thinking that the final one would be soon, and he wouldn't be there to suffer the consequences.
And in my head it's just: Harry makes Severus play Dress to Impress with him, Ron, and Hermione. :)
