Which philosopher said, "A man's most powerful opponent is himself?"

American psychologist and professor Dennis Vitley said, "Man's most powerful opponent is himself."

American psychologist and professor Dennis Vitley pointed out: Good mental preparation is either the key to the door to success or the iron lock closing the door to success. Therefore, to defeat others, you must first defeat yourself; because the most powerful enemy is not others but yourself.

On the road of life, everyone has many beautiful dreams. Everyone hopes to find their best position and realize their greatest value, but sometimes they are hit by ruthless reality in an instant. Crush. Many times, everyone needs to put a fire in their heart to rekindle some hope. Many times, everyone needs to sprinkle some water in their hearts to extinguish certain desires. A person will encounter thousands of opponents in his life, such as every race, every competition, every interest...the number is countless. Who is the biggest enemy in life and the most difficult enemy to deal with? The answer is right in front of you. The biggest enemy in life is yourself.