I do not own How to Train Your Dragon.
It all started with realizing that he used a different hand than his father. He was, what, three or four at the time? He honestly couldn't remember how old he was. It doesn't really matter, but it was when he noticed that he was different from everyone else in the village.
Stoic had made something that looked like stew and tasted something very different from it. But he was feeding his son without the help of his wife, and it was the best he could do. He had a village to take care of, learning to cook for others had never been in his schedule. But Hiccup's mother was gone, raising the boy fell on Stoic's shoulders. Maybe he could get Gobber to help him out. Two bachelors could raise a boy, right? He'd ask the blacksmith later.
The two had been sitting at the little table in the empty home, eyes down, eating in silence. Hiccup kept glancing at his father, trying to find something to say. The man was always so distant, so far from his son. That's when the boy noticed that his father was eating with a hand that was on the same side as himself. Their movements matched, like looking in a mirror. Which, wasn't right? Because, if he sat on the other side of the table, sitting next to his father instead of across from him, they'd be using different hands.
Starting from that day, Hiccup watched the village people very closely. He noticed everyone used the same hand as his father did. Their right hand, starboard, if you're on a ship. He was having problems remembering which was port and which was starboard, he'd figure it out later, when he was older, he was sure. But, everyone used their right hand, and he used his left.
He was different. That was the first time he felt alienated from his people. The first of many. He was different, he was strange. He couldn't let anyone know about this!
So he forced himself to use his right hand when others were around. When eating he'd remind himself to be right handed, not wrong handed (as he started to call it.) When his father taught him to use a knife, he practiced around Stoic with his right hand, and privately with his left. Because it felt better. It honestly did. But he was afraid to let others know of it.
Because as he got older, the more, erm, obvious differences stuck out. Long and lanky, rather than strong and muscular. Thoughtful and curious, rather than leap without looking. He was not a Viking. But there was one thing that kept him the same in the village, he was right handed around them. Even when he was older, fighting dragons in the ring, it stuck to the back of his head. He was better at hiding his left handedness than hiding Toothless.
And now, even years later, when dragons were roaming around the village and forests and living right along with the Vikings, his habit of hiding his left hand use was still there.
Because no matter how different you were, no matter how alike, no matter how shunned, no matter how accepted, there's always a secret that you hide. Even a silly little one like which hand you use.