Laugh
Although most might not audibly detect it, Riza Hawkeye had an incredible laugh. It wasn't one of those obnoxious, winded laughs or the nervous kind; it was unique and often silent. The only person on record to have ever made her laugh completely out loud was of course, Roy Mustang. It ran clear through his mind as he remembered how she had thrown her head back and let out the most beautiful, carefree laugh he had ever heard. He could also tell right away when she was doing one of her silent laughs, though it took some paying attention. He noticed that every time she did, her lips would curve slightly upward, and her eyes would get that brief glint of happiness before slipping quickly back into the professional reality of their jobs. But his favorite laugh (more of a giggle really) only occurred when his hand, or on slight occasion, his lips would pass around her belly button, making her jump a little and utter the wonderfully vivacious giggle. She might not have laughed often, but maybe that's what made it all the more special to him in the first place.