It's easy to smile just to make other people feel better. But when a person fakes happy, it has edges. Regular people may not see, but the people who count, they can see edges and lines where smile ends and the real you, the sadness (me) or the anger (Grandma) begins.
Real is...just being you. It's not letting yourself be defined by other people's opinions of you, of who they think you are, or what they expect you to be. It's refusing to let them squash you into the box they've built for you, and just being yourself, no matter what anyone else thinks. Because you're never going to matter to everyone, just like everyone's never going to matter to you. So you choose the people whose opinions you care about, and you be real for them.