While the basic principle of the Muslim belief is that ‘There is none other than Allah worthy of worship and Mohammad is his messenger’.
Prayer should always be directed towards God, and not to the prophets although we strengthen our faith through them. If we fear or revere someone too much, we often end up bowing down and even prostrating to that individual because getting into the fetal position is natural and ultimate body position of submission. Worshipping and submission are natural to human beings.
The political scene in some of the primitive cultures mirror idol and personality worship. We often see some overzealous religious group bowing down or prostrating to a religious leader, Sufi or a dead saint. They claim that dead saints rule their flock from the graves. Is a person with flesh and blood irreplaceable when it comes to a leadership position, even after death?
Humanity has always had the propensity to make gods out of the things they fear or cherish. The Romans, Egyptians and others converted such things as the sun, the moon, the planets, the oceans and many other things into gods. As such, many societies ended up with many gods.