Had he ever been embraced with love? Had his hand ever been kissed? These were questions that constantly haunted Severus's mind. And not because he was desperate to find a partner, but quite the opposite.
He had never felt genuine love in his life. And since Lily's outright rejection, which involved ungrateful mockery and public humiliation, he had no intention of ever getting close to anyone again, much less falling in love. But... his plan changed when a certain wolf defended him from the Marauders one night. Specifically, a full moon.
Sirius and the others already knew Remus's true nature; that much was obvious. And, in fact, they had already tried to use his lycanthropy against him once, in a cruel prank—in quotes—to assassinate Severus on a full moon night. It was disappointing for Potter and Black to see that Severus never headed towards the forest as they had planned.
So they tried again.
And this time, Snape took the bait.
One full moon night, a howl was heard in the distance, and atop the hill overlooking Hogwarts, Severus set off, only to encounter Remus Lupin, transformed into a werewolf by the Marauders. They were close by, and as Severus was about to run for his life—
What—?
Even he couldn't explain such behavior, but instead of attacking, the giant wolf assumed a defensive stance, positioning itself in front of him as if...
...protecting him.
Severus wasn't going to back down, of course not. He was about to reach for his wand when he noticed that, indeed, Remus, still under the effects of lycanthropy, was currently protecting him. More precisely, from the Marauders. So, though quietly, he murmured:
...Thank you.