But, actually, he chose a stag because it was large, powerful, and fast. It could survive a werewolf attack (assuming the worst case scenario happened). When the Marauders told Remus they were animagi.
This is funny but this closely resembles my actual prayers at night: "Dear God, please do not let Trump become president. Unless it is your will to destroy America as a part of your bigger plan, in which case I understand.