You get to optimize things like crazy. Instead of chopping garlic into little pieces, crushing it removes the acrid taste but keeps the odor. Using butter to toast burger buns instead of margarine basically doubles the quality. There's a timing & liquid quantity window for brewing tea, where you get the best tea.. though sometimes if you're making tea with milk, you want more tannins. The variations of tea also have more impact than variations of coffee. But probably because tea is cheap, it's not as much of a snob sport.
Eggs are incredibly interesting too. It's both beginner tier and mastery tier. It's your hackerrank equivalent - make spaghetti carbonara, make a french omelette, make poached eggs, make egg sushi.
I think it's sad that it's a minimum wage job and never attracts the kind of people who like to optimize things, besides the cafe niches.
Obviously pretty dystopian and my experience there were close to zero ethics. They used to try and bribe the smartest young kids by offering company cars if they quit school and trained as managers. The owner even tried removing the small change from the tills as most people don't complain if they are short a tiny amount so he could squeeze that little extra (not a viable strategy btw as a tiny minority will freak out publicly).