Asking in this way indicates a negative attitude how you are looking at yourself and others. You are right, - indeed it looks like as if we are our own enemies, because we behave in ways that are not favorable at all for ourselves. We are even destructive, not only damaging our body with junk food and eating habits that make us sick, filling up our system with poison and toxins, - we are also doing harm by exposing ourselves to influences that squeezes our mind into a frame that turns out to be a strait jacket. We are identified with it and see it as our 'personality' not being aware, that this is a conglomerate out of misinterpretation and manipulation, that makes us to puppets, consumer and victims. It seems, that we are our 'own enemy', because we suffer from our limited condition, but at the same time we are clinging on it. We are stuck in a game with ourselves, that gives us the feeling of existence, but at the same time holds us tied in it. It keeps us busy and so gives us a kind of feeling of sense and meaning, hunting and going for goals and values, that are introduced to us through the established mindset of this society.
Humanity is stuck in this still primitive step of evolution and holding on it, - as this seems to be the most important, so it is causing all the negative results in our life against we are fighting and giving the fault for it to the outside, but not looking at ourselves, realizing that we are the cause.
If we could understand this as a process and that we are in transition, than we wouldn't need to hold on our 'property' in form of a rigid mindset and we could explore our existence that of course goes far beyond our present condition. Then we could become friend with ourselves and with this also come together with others. Not to be confirmed in our feeling of existence because we believe or strive for the same common goals, but because we are realizing, that we are coming and going, being connected to the same *source*.