Trivia: Sam Rockwell said he received a call from Jon Favreau about playing Tony Stark in the first film, but never heard anything more about it. He ended up getting the part of Justin Hammer in this film through his friendship with screenwriter Justin Theroux.
Trivia: When Tony is flipping through his father's notebooks, he comes across a sketch of an object that looks like a cube within a cube with lines connecting the corners. This object is called a tesseract, which is a three-dimensional model of a four-dimensional object. Or in this case, a two-dimensional drawing of a three-dimensional model of a four-dimensional object. This is a foreshadowing of The Tesseract, one of the Infinity Stones, which plays a huge part in several of the other Marvel movies.
Answer: He wanted to do something nice for her, but since he is a pretty self-absorbed, shallow multi-billionaire, he forgot about her allergy. He remembered that there was SOMETHING about her and strawberries, but misremembered and thought it meant she really liked them. He makes a simple human mistake, not out of meanness or spite, but because he honestly does not remember.
Twotall