A person can be modest about their talent and careless about the effect they have on others.

Humility about your abilities is not the same as care about your conduct. Someone can genuinely downplay their gift and still be late, sharp, unreliable, or quietly demanding, because those are separate habits, and modesty about the one tends to buy a great deal of credit for the other. The self-deprecation is sincere, which is exactly what makes it easy to miss.

Judge people by the state they leave others in rather than by how they speak about themselves. Ask the same of yourself: not whether you boast, but what your week cost the people nearby.