The article presents the dependence of the behavior from the self-image and formation of self-image under the infl uence of others. If we treat aggressive man calmly and without fear, we give him the signal that „you are good”, and if we are convincing, then behavior of the aggressor becomes good, because it is consistent with his positive self-image. This method can be used in upbringing of children, resolution of confl icts and preventing aggression. The article gives a number of examples where people dealing aggressors without fear and with peace, came out safely from a very difficult situations.