To sum it up, two words: courting death.
But it can't be purposelessly courting death, purposelessly courting death might end up like the Plant Spirits, coming muddle-headedly, dying muddle-headedly, opening and closing their eyes and somehow surviving the tribulations.
When a Mayfly courts death, it must first enter the world before doing so. Thus, Zhao Cheng'an in his first life found a boss and mingled with humans. As long as humans treated him slightly badly, making Zhao Cheng'an feel dissatisfied, resentment, or regret, he could ascertain his failure in surviving the tribulations, then freely let himself go.
