What does Percy mean when he states the best people get the rottenest luck?

When Percy says "the best people get the rottenest luck," he suggests that those who are kind, good-hearted, and deserving often face the most difficult and unfair challenges in life. This statement reflects a sense of injustice, highlighting how virtue and goodness do not always lead to positive outcomes. It emphasizes the unpredictability of life, where bad luck can befall even the most admirable individuals, suggesting that success and happiness are not solely determined by one’s character or actions.