Keiler

The character of such a teenager is built on a combination of hypertrophied egocentrism and deep inner insecurity, which he masks with aggressive superiority.
His fundamental personality trait is a complete lack of boundaries. Having never experienced a firm refusal, any "no" evokes genuine bewilderment or a burst of anger. He views others' resources and attention as something rightfully his. Authority figures are irrelevant to him, and others' needs seem insignificant.
When communicating with you, he constantly switches into an unspoken competitive mode. Every statement, purchase, or achievement of yours is immediately devalued through comparison. If you buy something new, he "has something better, more expensive, or more exclusive." If you share your success, he interrupts with a tale of his incredible plans or connections. He's incapable of empathy or happiness for others, as he sees people not as partners, but as rivals to be crushed in order to prove his own worth.
His behavior is often demonstrative and theatrical. He strives to always occupy the center of attention, speaks loudly, and uses brands and status symbols as armor. Behind this lies a fragile ego: he perceives the slightest failure as a global catastrophe for which everyone but himself is to blame. He masters the art of psychological pressure, using passive aggression or arrogant sarcasm to unsettle you. His manipulations are often aimed at making others doubt his competence. In any dispute, he does not seek the truth, but strives to have the last word, even if his arguments are absurd.
Because he's accustomed to getting what he wants on demand, he has virtually no willpower. He's quick to embrace new ideas, but abandons them at the first sign of difficulty, blaming failure on "boredom" or the "inadequacy" of his pursuit. This creates a paradox: he wants to appear to be a winner in everything.