MONSTER TRUCKS

So apparently not everyone had noticed this, but… 

Hiccup is left-handed (this is the part pretty much everyone knows), BUT he actually tries to use his right hand sometimes when trying to “fit in” with the others, when he’s trying to act in a “traditional” way (and usually failing). 

The most prominent instance of this, I think, is the part where he finds Toothless tangled in the bola-ropes in the forests, and plans to kill him. During the “I’m going to cut out your heart…”/“I’m a VIKING!” speech, he’s holding the knife right'handedly. 

But then he can’t do it, because he’s not like everyone else, so instead he cuts the ropes to let Toothless free… And he uses his left hand to cut those ropes. 

He’s also seen holding weapons (or, well, trying to) right-handedly in dragon training. 

But yeah he’s clearly left-handed; he writes and draws with the left hand, he uses his left to do metalwork and so on and so forth. 

He’s fundamentally different from everyone else, and while the filmmakers never brought up Hiccup’s handedness the way the books did, they did something a bit more subtle with it. When Hiccup is doing something different, something he’s good at, he’s using his left hand, and that’s when he succeeds at stuff. He released Toothless from those ropes left-handedly. He made that artificial tailfin for Toothless left-handedly. He does things others don’t do, and that way, he makes new discoveries others never did before. 

It’s when he tries to be just like everyone else when things don’t work out for him. And the filmmakers subtly made him use his right hand during many of those moments. It’s what everyone else is doing, and they seem to succeed at it without too much trouble, but Hiccup isn’t just like them, so when he tries, he fails.