Defense mechanisms are unconscious psychological strategies that help us to cope with reality whilst also preserving our self esteem. Normal, healthy people use them regularly. Examples could include humour, thought suppression or sublimation (transforming negative emotions into positive actions - like helping a friend when we’re feeling sad or down). They only become pathological when they lead to problematic behaviours that compromise our health or relationships. Examples of unhealthy defenses include:
Acting out: This is directly expressing an unconscious impulse without realising what is driving the behaviour.
Fantasy: This is retreating to a fantasy world to escape, or resolve, conflicts we are battling with.
Idealization: This is unconsciously choosing to see another person as being more ideal or perfect than they really are.