Oh yeah. Everybody in the fandom is always so surprised about my feelings for these two.

Snape:

I agree that he was complex and had many issues that made him interesting and fascinating. But honestly, I could just never get over the fact that he was also a giant asshole. I also resented the fact that I was expected to suddenly forgive/like him when I learned about his past in the seventh book and forget what a huge douche he had been the six other books. For me, his love for Lily (which by the way I saw as totally obsessive and unhealthy) and sacrifice, while brave and noble, did not and could not erase that fact. He was a bully and he was irrational and he was bitter and immature.
It all made him VERY interesting and complex. But I still didn’t like him that much. 

Sirius:

He’s just not my type of character. I don’t hate him, but I don’t particularly like him either. I feel for him a lot. He went through a lot of really terrible things and nearly lost his mind in Azkaban. He’s strong and caring and fiercely loyal and he loved James and Lily and he loved Harry and he cared. Objectively speaking I can see all that, but in the end, he just annoyed me a lot. He’s impetuous, and brash and very arrogant (he was like that before Azkaban as well). And I don’t know, I’m annoyed with people like that, so. I could not completely feel for him, because even though I understood why he was that way, I still resented his inability to listen to people around him, who might know better and to assume that he was the only one that really cared about Harry and…I don’t know. It just made me roll my eyes a lot, even though I understood why he was that way.
I am really sad that Harry lost him, though.