Tea

I would say that there is not much of a "culture" around green tea specifically, as there tends to be a much stronger culture of black tea, at least where I am on the east coast (Hot black tea in the Northeast/New England, iced/sweetened black tea in the Southeast).

As others have stated, most Americans would be familiar with it in teabags or bottled green tea, and so many who do end up trying it don't enjoy it because they end up trying a bitter, lesser-quality version of it. Others may be familiar with it in Japanese or Chinese restaurants, where the quality is hopefully better, but this probably cannot be rightly called American green tea culture.

In my experience, it is the sort of thing where the green teabags might be the only ones left in an office meeting room because, while someone thought to stock the meeting room with green tea in the first place, all the others have been used up first and then someone has forgotten to refill them.