Equals bow to show respect! Stronger bow to show generosity! Wreaks bow to take advantage and forgiveness!
When two persons with equal power and capabilities bow to each other, it is an act of showing respect. When a stronger person bows to a weak person, it is a sign of generous nature of the stronger. The weak bows in front of the stronger when he look for forgiveness of the stronger or seek help and favors from the stronger to fulfill his desires.
It is a common human nature to observe. In daily life we come across many people who easily give in. One must be aware of such situations and understand the hidden purpose one is acting upon.