I think, not so much *she* is a jokester, as the world around her is unfamiliar or subtly off to her (since she grew up only seeing 'life in America' on the television, and so has a skewed notion of how it works, only exacerbated by coming over her and living in Tony's bazillion dollar AI-curated compound, which is *nothing* like 'real life'), playing the same fish-out-of-water role that Chris Evans got to play so effectively with Captain America (getting plenty of humorous bits, but not so much because he's a joker or a snark machine, like Tony).
One little aspect that could be re-visited from Civil War is that Vision, for all his amazing abilities, has no sense of taste, or real understanding of human cuisine, so he could be screwing up every meal he gets his hands on, with the best of intentions.
"The recipe called for a 'smoky' taste, and I remembered that burning plastic produced copious amounts of smoke, that had a strong odor to it [long story snipped] and after they all left, the fire marshal stayed behind to tell me never to do that again..."