Cellular Observation

The object that I chose to describe to my friend over the phone was a Darth Vader coffee mug.
I started describing the object by its color, which is black and it is also shiny. I use it mostly during the morning time. That should have been a good indication that it was some part of a morning routine. I informed my friend that it is breakable and that it needed to be cleaned after every use.
After my friend could guessed it was a coffee mug, I asked what clues was really helpful. He said it was not the object clues themselves, it was its function. Primarily used during the morning and also breakable. He also said that he uses something similar to it in the morning.
What I learned from this exercise was being descriptive of the object