Every line of MaskedSaint's "So That I'll Be Me" pairs a role the speaker will play with the reason for it. Be indifferent, so nothing hurts. Be cruel, so no one can predict you. Be iron and steel, so love can't get in. The speaker isn't boasting about being tough. The poem reads like a list of defenses, each one built because of some earlier pain, though the poem never says what that pain was.
The contradictions give it away. The speaker will be "a bad person, so that I can smile," and smiling "so that I fully understand," which suggests the cheerfulness is another mask. The tone is cold and guarded, but a sense of tiredness sits underneath. Only the last two lines drop the "so that" pattern. There, the speaker simply says "I'll be me" and claims not to care about judgment. After so many disguises, the poem leaves open whether that is real freedom or one more shield.