Hopper has been hiding Eleven in his cabin, looking after her and making sure the 'bad men' don't take her away, and in doing so, he basically turns into her father.
Seeing as he lost his daughter Sara when she was only really young, it's HEARTWARMING!
Now, a Reddit user has noticed a small detail that shows just how much Hopper loves Eleven like his own daughter. (Aside from like, legally adopting her as 'Jane Hopper' at the end).
During the show, Hopper always wears a blue band around his wrist. The same band can be seen in Sara's hair before she fell ill and underwent chemotherapy.
You see the band then worn on Hopper's wrist while reading Anne of Green Gables to Sara while she's sick. Ever since Sara passes away, he wears it.
Then, in one of the final scenes of season two, while Eleven goes to the Snow Ball and dances with Mike, you can see the same band on her wrist.
WE ARE NOT OKAY.
TAKE A LOOK: