A bad friend is nothing but a spy

Friend: A potential enemy with whom relations have not yet deteriorated to all-out war

Enemy: A friend whose mask has fallen

A bad friend is is worse than an enemy, an enemy you can see and avoid, but to detect an insincere friend is hard

Would a robber break in your home at night beating drums? Nope. This is how those who want to take advantage of your life come: Full of smiles and promising sincere friendship!

A bad friend secretly plots your downfall