Scripture Union had an audio-visual presentation called The Stranger in the 70s, where in a fictional town everyone had a badge proclaiming their position by a number. The stranger arrives and refuses to wear a badge. This causes chaos as he told people they had a value not determined by a badge, and they started to refuse to wear such badges, but the rulers were displeased, and the stranger gets lynched by an angry mob. Societies still play great value in social status and power.
The disciples seemed to have missed the bit about Jesus' impending death, but had taken on board his future kingdom. So, they asked for positions of authority in it. The motives of the disciples was probably ambition, maybe their mother's. Maybe James and John felt superior to the other disciples. Jesus had to clarify misconceptions.
1. Before glory, a time of trial by way of the cross.
2. The greatest in the kingdom is the servant of all. Jesus turns the order of society upside down. In heaven, success is measured by criteria different to the world's.