For me, it wasn't even that I was attached to Sirius -- I liked him, but I had kind of guessed he was going to bite it -- but that by that time I was getting to the point of, "Okay, I understand that 'torment the hero' is sort of how the genre works, and I accept that these books would be boring if Harry's life was happy and rainbows all the time, but he is like 15 so could he maybe have ONE WEEK where he doesn't make some mistake that HIDEOUSLY RUINS HIS OWN CHANCES FOR HAPPINESS EVER AGAIN."