What is conscientious to a fault mean?

"Conscientious to a fault" refers to a person who is overly diligent and responsible, to the extent that it may become a disadvantage. While being conscientious typically involves a strong sense of duty and attention to detail, when taken to an extreme, it can lead to stress, indecisiveness, or an inability to delegate tasks. This phrase suggests that the individual's commitment to doing things right may hinder their effectiveness or well-being.