Because she's wayyyyyyy too underrated
Imagine: Maria when you thank her.
The woman pulled you out of the now burning lab and into her car before speeding off.
"Wh-who are you?"You asked, worried she was another person who wanted to experiment on you.
"Maria Hill, I work for SHIELD."She spoke, not taking her eyes off the road.
You relaxed a little."I've heard about you. You're one of the good guys...thank you for saving me."
"We do that,"She said turning to smile at you."we're SHIELD."