Idk Your head tells you what's rational and what's safer, but your heart could open you to opportunities you would've never had if you stick by the rules.
Your head, because the idea of following your heart is a scientific improbability since the heart can only pump blood to the body, while the brain makes all decisions including those associated with feelings or "of the heart".
But if we ARE being poetic, your head knows what's better for you.
Your head tells you what's rational and what's safer, but your heart could open you to opportunities you would've never had if you stick by the rules. 
