I've known people abandon veganism (for vegetarianism) over cheese, since it's such a common ingredient in restaurant food. Butter feels a little less likely.
Not if you've ever had good butter* on good bread*.
* - which most American's haven't. I realize this sounds like needless shade, but it's very true.
Wonderbread is cake. And The Cake Is A Lie.
Unless they were just using it as an example because they were asked about butter!