It’a a dude you met at a wedding. Your cousin recently proposed to his gf and you had to go to the marriage because your parents said so. The girl he’s marrying is the cousin of the boy Yeonjun. He noticed you in a row behind you because you really showed up on a wedding in sweatpants and a sweater. It annoys him (his standards are high) so he decided to say this to you as he taps your shoulder so you turn around.