Curate, connect, and discover
Snarry and Tomarrymort are the most mentally stimulating ships I know
I ship both Snarry and Sirry, and one of the main compelling aspects of it is the journey Severus and Sirius have to take to finally see Harry as his own individual, separate from his parents completely, and love him for it.
Something about the men who turned Harry's life upside down...