OK, we admit it - McKayla Moroney isn't a meme, she's a person. But she's a person who became a meme, so that still counts in our book! There aren't all that many people out there who avidly watch women's gymnastics, so Moroney is far better known for her meme fame than anything she'd achieved in her career before that point. Her face has been used as a byword to mean 'I'm not impressed,' based on a photo of her looking disappointed with herself after only securing a silver medal at a tournament.
At a later tournament, Moroney went on to win a gold medal, and looked a lot happier about it. The pictures from that event didn't get her the meme treatment, sadly, so she'll always look disappointed to us! She's now completely retired from the world of gymnastics, and is focusing her energies on trying to make a new career in music.