If what is formative is what you struggled for then we can say I:
– fought tooth and nail for reason and rationality (and no, not rationalization or false logic or emotionlessness)
– fought tooth and nail to go to a real university and not just a nice safe nurturing college
– fought tooth and nail to major in something intellectual, not just music or art appreciation
– fought tooth and nail not to be forced to housewifedom, not to get stuck out and have to marry someone to survive.