I'm fine with the back story, but then I've generally enjoyed every back story.
The whole point of Hashirama's story time is to give Sasuke some desperately-needed perspective. He needs to know his clan had a rather noble passion, but their shit didn't smell like roses. And he needs to know just how fucked he's going to be if he holds on to all that anger. You'd think Itachi's story would have been enough to wake him the hell up, but apparently not.
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