A biochemist with not one, but two PhDs, Jemma Simmons proves that she is both the head and the heart of the Agents of S.H.I.E.L.D. operation. We love her because she is a brilliant scientist and strategist, but most of all, because she does her job expertly while building meaningful (and adorably hilarious) relationships with all of her fellow S.H.I.E.L.D. agents. On multiple occasions, it is her problem-solving abilities and vast knowledge, including medical expertise, that have saved the lives of the entire team she works with. It doesn’t hurt that she is in a perpetual witty war of words with her scientific counterpart, Leo Fitz.