>>3497696-She'd probably make a small frown and be slightly miffed while saying "はいはい、聞こえてるんだよ!" along with lightly hitting my forehead with the side of her hand. You made me picture a cute image, thank you!
-It depends on the kind of promise, but if it's minor promise to hang out she'd feel bad and most likely just apologize to them for it while promising to spend time with them doing something fun or meaningful next time, they would understand. If it was a more important promise though, the very first thing that would happen is her friends would get worried. They know she isn't the kind of person to break an important promise with them unless something important happened. I feel like Mai would also feel bad and apologize in that case, especially if it was important for the friend in question, but I'm sure none of her friends would ever hold it against her.