because of the old times
Because of Tsunade...
Because deep down she knows she will never catch up to Naruto and Sasuke.
Because deep down she knows she will never catch up to Naruto and Sasuke.
I don't think it was nostalgia. On the last page she looked very sad so I'm guessing Katsuyu told Sakura what happened to Tsunade. Or else it's because she knows Sasuke is still evil; that's what everyone was talking about before it showed her looking sad.