Joseph Stalin developed through his life a sense of inferiority due to diverse factors. Most of them are found in his childhood; he had a difficult infancy as he underwent severe physical and psychological problems. His father was an alcoholic that brutally beated him. During his education to become a priest, he was not a very clever student and as result he was also beated by the priests. He never finished his education making him feel fool. A negative self image was also formed due to scars in his face provoqued by smallpox; also one of his arms was shorter than the other and half-paralized.
We can now see the reasons he felt inferior, later in his life he invented almost everything about his life trying to feel superior. When meeting with great revolutionary intelectuals, as Lenin, that sense of inferiority came back.