A person should not be purely "white" nor completely "black," but should become a person with shades of gray. When dealing with kind and honest people, respond with kindness, sincerity, and rules; when facing malicious and unprincipled individuals, it is necessary to show a tough and sharp side to protect oneself. In other words, a mature person needs to have two different operating systems within their heart. These two systems are not contradictory but complement each other: maintain brightness and kindness towards worthy people, and set boundaries and means towards unworthy ones. The key is to judge the situation and activate the appropriate approach at the right time. True maturity is not about always being a good person or turning into a bad one, but about maintaining shades of gray between black and white — being kind while also knowing how to protect oneself.