Personality
Snotlout is highly arrogant, bordering on narcissistic, and prone to grandiose delusions of perfection, popularity and extreme attractiveness, and consequentially his egomania causes him to have a huge problem with authority or being able to admit responsibility for his mistakes or misdeeds, for which he always has some terrible justification. He appears to consider himself the smartest and strongest of the teens and wants to be praised and admired accordingly, despite the others usually considering him an annoying, immature idiot with a colossal ego. His selfishness and egomania cause him to often be inconsiderate and exploitative towards others, and will often put the others down to make himself look better. In interviews, Jonah Hill has said that deep down Snotlout knows he is not the best but still wants to be thought of as such, implying his vainglorious posing is more about overcompensation. He likes to think he can handle everything, but when he can't, he is not above asking for help.
From the glimpses of his family in the television show, it is easy to see how Snotlout is a product of his upbringing, since his father, Spitelout, is shown to be just as arrogant and disrespectful as his son, and places great pressure on Snotlout to meet his incredibly high standards and preserve the family reputation. Earning his father's love and approval clearly causes Snotlout a great deal of insecurity and anxiety, and in this way he is similar to Hiccup, though it is unacknowledged, since Snotlout either keeps it to himself or is in denial about his father's clearly unfair treatment of him.
In the television series one of Snotlout's more outstanding traits is his adversarial relationship with Hiccup, whom he often deliberately disrespects and ridicules. In that he is not unlike Alvin, who did much the same thing to Stoick. Snotlout will regularly attempt to undermine Hiccup in front of the others by trying to appear more knowledgeable or worthy as a leader, but since he is neither of these things, he often just ends up making himself look like an idiot. Snotlout has stated that he thinks of Hiccup and himself as arch-enemies and states that they are not friends, though this view is largely unfounded and not reciprocated in any way by Hiccup, who refers to Snotlout as his friend despite being regularly exasperated by his behavior. Snotlout's antagonism of Hiccup is partially a result of his dislike of authority figures, but is also implied to stem from deep jealousy of Hiccup's standing within the tribe, the respect he receives from the other teens despite being previously being thought of as a runt, and (probably most of all) his close, semi-romantic relationship with Astrid, whom Snotlout has a huge crush on and relentlessly, arrogantly flirts with, despite Astrid being repulsed by him to the point of nausea.
