Why must you wake the sleeping Uchiha when he's been happily napping in the corner of the box of muses.
36. What makes them feel guilty?
There isn't much that doesn't cause a pang of guilt in his heart. But the biggest factor of them all would lie in the fact he was a part of the Akatsuki, the very organization that wanted to cause his village--his home--Harm of the highest degree...And he could only pretend to be their ally until his own brother would bring upon him his final breaths.
And of course, Sasuke's own hatred of of him.
Itachi is the biggest keeper of secrets in all of the five great nations--And that goes without saying, especially if you've read the manga.