2. Tony Stark's Food Habits
Robert Downey Jr brought a fair bit of improvisation to the film, just as he had to Iron Man when Jon Favreau had encouraged him to go off-script as much as he could to improve character moments. The "doth mother know you weareth her drapes" was all down to him and so was the Galaga moment.
In a stranger moment of improvisation, Downey Jr also hid food hidden all over the lab set. He hid it so well that nobody else knew where it was so they just allowed him to continue. So when he offers Captain America a blueberry in one tense scene and when he's eating, it wasn't in the script, Downey Kr was simply hungry.