You cannot predict what will thwart your plan of total magical domination. Sometimes, a young wizard is all it takes to ruin this plan. Here are some tips to avoid that.
#1 Be careful of the power of a mother's love
#2 Recruit people who will have your back (of the head)
#3 Get a new pet (preferably big and slithering)
#4 Build your own cult of evil wizards