Natasha: Don't. Don't do that to yourself, Clint. This is Loki. This is monsters and magic and nothing we were ever trained for. 

vs:

Bruce: Even if I didn't just...there's no future with me. I can't ever...I can't have this, kids, do the math, I physically can't.

Natasha: Neither can I. In the Red Room, where I was trained, where I was raised, um, they have a graduation ceremony. They sterilize you. It's efficient. One less thing to worry about. The one thing that might matter more than a mission. It makes everything easier. Even killing. You still think you're the only monster on the team? 

  This is why I can’t get on board with Natasha/Bruce. While comforting Clint, she lifts him up, assures him he’s not the monster he thinks he is. While comforting Bruce she takes herself down to his perceived level. 

BruceNat through the Marvel Universe [1/?]:

Like excuse you, did you NOT see how she looked at him in the first movie when they first met?

Avengers:

Keep Natasha going to get Bruce to recruit him

Keep Natasha glancing at him during the meeting

Captain America: The Winter Soldier:

During a moment when Natasha is trying to set up Steve with a date, Sam or Steve ask if she has anyone

She replies with “Maybe”

Iron Man 3:

During the end credit scene with Bruce

After Bruce wakes up, Tony questions him on his love life

Bruce replies with something about he has no idea if it’s going to work

Age of Ultron:

Keep the awkward flirting

Only keep that

Well change the scene with the shower around

Natasha makes the joke that she should have been in there with him

They are both a little “eh” about it

They don’t talk about it

Thus UST

Civil War:

Two ways:

BEFORE WAR:

Tony and Steve are talking

Tony mentions Bruce’s crush on Nat

Steve asks Nat about Bruce

She shurgs

AFTER WAR [BEGINS]:

Tony asks Natasha about Bruce

Or

Tony tells Natasha about Bruce’s crush

Or: that Bruce has a crush, but doesn’t mention it’s her

Infinity Wars:

PART 1:

Bruce and Natasha have an awkward meeting

They fight like a married couple over something small

Some cute fighting back to back

PART 2:

Like that’s the Bructasha I want.

Not the AOU forced crap.

JUST THE TEASING IN THE FIRST MOVIEEEE WAS JUST SO RIGHT.

WHY FUCK IT UP JOSS. YOU WERE GOING GOOD WITH IT.