Cilantro
Cilantro: you either love it or hate it! The author of this page, for example, enjoys cilantro in tacos and other Mexican meals, whereas many people band together around their hatred of the spice. Cilantro-haters express themselves in every way possible, including anti-cilantro t-shirts and anti-cilantro websites! Cilantro-haters complain of the smell and taste, while others cannot understand what all the fuss is about.
Ground or whole, cilantro makes a lovely addition to Thai, Chinese, and Mexican dishes --- for those who don't shun it like the plague.