The mule is the symbol of slowly movement through life, silliness and stubbornness. The dreamer who sees the mule in his dream is suffering from the fact that he is only able to do the hard and worst work. Alternatively, the mule is very much respected animal that helps people to di the jobs. The mule could show the quiet and slow aspects of dreamer.
Read more about dreaming of Mule in other dream meanings interpretations.