Incredible actress
on supergirl she essentially plays three people.
kara danvers the secret identity (clumsy cute dork sucking up to cat)
supergirl (serious, determined, proud, regal yet gentle and loving to everyone she tries to help)
and
kara zor el (the real person, mostly when she's with alex at home).
when she cries or is sad, you can't help but feel the raw emotion.
when she turns evil, it is strikingly opposite of anything we've previously seen from kara (vindictive, sarcastic, selfish, arrogant).
and melissa plays it all to perfection.