Hangovers are only a mix of dehydration and the toxic byproducts created when the body breaks down alcohol. It's a simple matter for a healer of her caliber to get rid of the toxins, redistribute her cells' H2O content, and make herself feel as fresh and healthy as a rose.
She never does. The hangovers are a bitch, but she deserves them. Oblivion is a myth, one she can never reach anyway; she's been drinking too much for far too long for any kind of alcohol to still affect her enough.
She's never gotten used to the feeling the morning after, though. The heaviness and the bleakness and the pain.
She tells herself that at least she'll know better next time.
And then she does it again anyway.
She doesn't heal herself, because she deserves it. Reaching out for something impossible, knowing how much she will hurt on the way down, but still hoping that this time it will be different -- she knows what she's getting into.
She can't stop drinking anyway. She can't stop hoping anyway.
This time... this time, it will be different. Except it never is. The world doesn't work that way.
She doesn't even drink to forget Dan and Nawaki's deaths anymore. Neither were her choice, neither were her fault. She accepts this, now, mostly. But she drinks to forget other things. Other things that she could have prevented, other things she should have seen coming, other things that she should stop feeling, because they're ridiculous and he doesn't deserve them anyway, he doesn't deserve her hope and her missing him and his sarcasm and his sense of observation and his cool that tempered their hotheadedness so well, he doesn't deserve her missing him like one might miss a limb or a sense or, well, or a loved one. Like one might miss a teammate, a third of one's self.
He doesn't deserve her still loving him and his quirks and his faults and his twisted mindset, still feeling his absence like an empty space where he should be, still feeling the imbalance between their third and her.
He doesn't deserve any of that, but he has it anyway. And she can't let go. So she drinks, to forget how it feels to miss a traitor and a murderer.
But all these feelings, they're not hers to bestow. He has them, and she can't take them back, even though she doubts he even wants them, or notices he owns anything like them.
She knows better. She still does it anyway.
She knows better than to stop Sakura. Sakura is like her, smart enough to know better, stubborn, stupid enough to do it anyway. To hope anyway.
When she brings Sasuke back, Tsunade will stop drinking.
This time... this time, it will be different.