Mules (and donkeys) have been labelled “stubborn” for centuries, but it is really only an abundance of common sense and a strong desire for self-preservation that might make them inclined to resist.
Mules and donkeys actually have a natural attraction to humans. When treated with patience, kindness and understanding, they learn to trust and obey. If they are treated with force and abuse, they are not likely to comply with your wishes. If only a mule could talk, most people would be surprised at how smart they really are!
Information courtesy of http://luckythreeranch.com/website/mule-facts/