There’s a surprising number of ingredients/dishes in world cuisines that can mess you up or outright kill you if not prepared properly. Fugu is probably the most infamous.
But there’s no shortage of foods we have to alter or trim into edibility, and some can even be found in grocery stores. Taro root, leaves of rhubarb, most acorns, parts of the edible nightshade family, olives.
To me, they always beg the questions of how did we figure out the solution to rendering them edible, and how long did it take?