What does the following statement mean they pick the most dangerous enemy they can find and it's themselves?

The statement suggests that individuals often struggle with their own inner conflicts, insecurities, or negative traits, which can be more challenging than external adversaries. By labeling themselves as their "most dangerous enemy," it highlights the idea that self-doubt, fear, and personal issues can hinder growth and success. This introspection points to the importance of self-awareness and the need to confront and overcome one's own internal struggles.