To dream of the mafia represents underhanded behavior doesn't allow morality or guilt to stop it. Ignoring the rules, cheating, lying, or taking the "shadier" route to achieve a desired outcome if needed. A willingness to use an underhanded approach if it's in your best interest. Getting what you want no matter what. The mafia may represent your desire to keep a situation the way it is and resorting to whatever dirty tactics are required to do that.
Alternatively, the mafia may represent a person or situation that you feel you can't refuse. Feeling manipulated or extorted. Fearing making a mistake or asking for help. Being stuck between a rock and a hard place. A sign that you may need to be more assertive about confronting someone.