An essential goal of an enemy is to have defeated you. To have altered your course from their actions, to have changed something in you to no longer compete against them.
An essential goal of a friend is to have supported you. To have altered your coarse from their actions, to have changed something in you to reach further towards your potential.
An enemy and a friend have similar objectives, to change you. This makes it critical to distinguish your friends from your enemies. By clearly interpreting and applying for yourself their change efforts, both can help you to learn and to grow from your efforts. A friend and an enemy can help us to succeed when we take the direction of change upon only ourselves to the end.
We learn from friends that ask us questions and we can learn from enemies that question us. Either stimulus requires your response, focus to continue learning with both.
You ultimately keep the score of whom are your friends or enemies. Either way, know the difference and progress from their actions.
“Always forgive your enemies; nothing annoys them so much.” — Oscar Wilde —