I love Black Widow (Scarlett Johansson). I love the Hulk (Mark Ruffalo). But Natasha and Bruce did not work together. It felt like Joss Whedon (who came up with this pairing for "Avengers: Age of Ultron") had run out of ideas of things to do with Natasha, besides give her a man to comfort and console, so he came up with this relationship. It's best to forget this ever happened.