Sometimes they should.
Most of the time? It's just the path of least resistance when compared to self-ownership and self-growth.
Worth noting... Judas and John has the same mentor.
What was the difference between the two?
If you can tell, you can pick which story yours will be like.
"The call to be a disciple of Jesus Christ is open to everyone, but we don't get to write our own job description." - Francis Chan
"...whoever wants to become great among you must be your servant, and whoever wants to be first must be slave of all." (Mark 10:43-44)