To be fair to Gaara, he had a VERY good excuse (the entire village from his father down trying their damnedest to break him), and as soon as he got one friend (Naruto), he turned himself around to the point that you wouldn't recognize him. Ei and Oonoki... you have a point.
But Sasuke still has the fact that the instant Madara/Kaguya were defeated he immediately tried to take their place, and tried to kill Naruto AGAIN because Naruto was the only person who could possibly stop his plan to take over the world.