It has nothing to do with how smart, rich, or friendly someone is. It’s whether or not they self-reflect.
Self-reflection means taking the time to think about your past actions, analyzing them objectively, and then determining what you’d change and do better given another opportunity. Not everyone does this. In fact, it’s much more the exception than the rule. One of the biggest tells is when someone sincerely apologizes for something they did wrong, and recognizes they should have handled things differently. That’s a telltale sign of someone who can self-reflect, and is capable of positive change.
The ability to self-reflect is also a useful indicator of whether a relationship is sustainable. If one partner in a relationship is unreasonably stubborn or incapable of analyzing their own behavior, it will be difficult to get past even trivial disputes, stymying any potential for growth. On the flip side, when both parties are willing to concede their own faults and work on improving themselves, the relationship is set up to flourish.
Lastly, self-reflection is an invaluable exercise for achieving personal growth. Whenever I reflect back on my own life, I often discover numerous instances when I acted in a way I’m not proud of, and wasn’t a great friend, son, or partner. It’s painful to admit these things, but this self-reflection was an essential first step towards self-improvement.
None of us is perfect. But self-reflection allows us to mitigate behavior and actions we’re not fully satisfied with by first acknowledging it, then taking the necessary steps to make things right and change ourselves for the better.