One wouldn't necessarily think it, but Edward Elric was an uncannily convincing actor. He wasn't very good at hiding his rage, he wasn't very good at hiding his glee, and he certainly wasn't very good at hiding his embarrassment, but he was somewhat skilled in the deception of masking his sorrow.
He laughed—open-mouthed and far too loud—he yelled(with just a tinge of hysteria flanking the outskirts of his tone), but most often, he smiled.
It was a curious thing, that smile. It morphed and mirrored so many other aspects of his persona that it was almost impossible to discern that the twitch of golden brows, or the dip of sapphic eyelashes was indeed the forerunner of some irrevocable pain. It was painful, really, the way his lips curled back and bared his smallish, almost pointy teeth, the way his eyes would shut after a while, in a parody of peaceful countenance—it was so terribly painful, really, the way he would smile when he was about to cry.
...After a time, Roy grew rather sick of the act. As he did with most things that annoyed him—Hawkeye's gun was a separate section, because quite frankly, he wouldn't dare mention HQ's firearms restrictions to her—he sought to rectify the situation.
"—and like always, this entire mission was a fucking waste of time, and could have easily been corrected with an inbred sheep as field agent," drawled Edward lazily, the epitome of boredom and insubordination, but there was a slouch in his stance not born of petulance, and his eyes seemed darker than usual. Worrying about his quest again, no doubt—the boy seemed to be doing that as of late. Roy sat up straighter in his chair, and held up his hand in a gesture of silence.
"Fullmetal, I have new orders for you."
Edward, upset about being interrupted so offhandedly, scowled and told his superior officer just where exactly he and his orders could go. Roy smirked, not at all put-off.
"Your newest mission, Fullmetal, is to smile like you mean it."
The blonde blinked at him, face working in a paroxysm of perplexion. "...What?"
"You heard me. It's so off-putting, this show you're putting on. I'd really rather see your smiles be honest ones."
"There isn't much to smile about," Ed groused, fixing the older man with a pointed stare, "and most of it's your fault."
"My fault? Oh, is it?" Roy's smirk threatened to break into a grin. "Would it be something, perchance, that an evening of dinner and coffee could rectify?"
For a moment, Edward looked surprised, then a red stain spilled across his cheeks. "I'm...ah...busy tonight. Some other time, maybe."
But as he spun away quickly and headed for the door, Roy noted that he wasn't able to hide his pleased smile.