self-conceited and insolent on account of one’s ability ? 你應該謙虛點，～要不得。You should be a bit modest. It is no good to be self conceited and insolent on account of your ability.
矜才使氣jīn cái shǐ qì
矜：驕傲、矜持；使氣：意氣用事。指依仗有點才華就意氣用事。rely on one’s ability and act on impulse, self-conceited and insolent on account of one’s ability