I just had this thought, but I was wondering if any of you were to be put in a pre modern society, and was for any reason given one of the three titles, which one would you rather be? Since there titles are often self proclaimed, I'll go by how they can be defined as..
Lord: Ruler of a small plot of land that answers to a king.
King: Ruler of a decent sized plot of land.
Emperor: Ruler of a vast amount of land.
And how would you administrate your territory?