I worked fast-food at Braum's (an Oklahoma-based ice cream shop that runs a MASSIVE dairy ranch here in the state). The ice cream is amazing and varied and not too expensive. However, after being hired, I realized I wasn't cut out for fast food. For training, I was made to watch a video on how to use an ice cream scoop to roll the perfect-sized ball of ice cream. Whatever.
Afterwards they put me out front and told me to get to work helping customers. The first person ordered a cherry limeade. Now, I love these things myself but had no clue what the ingredients were, let alone how to make one! Apparently there had been a poster with instructions at some point but it was gone now. I got a cup, partially filled it with ice, then put some soda water and cherry syrup, plus three real cherries in it. I had to resist the temptation to take a "test swig" and handed it to the customer with the caveat:
"It's my first day and I've never made one before. Please try it and if it's awful, we'll make another one."
Luckily it was acceptable (or the person was trying to be polite about it) and they paid and left.
I was eventually labeled "hopeless" as I could not figure out how to make milkshakes, fry the fries, etc. In my defense - no training and everyone was too busy for me to shadow them. My job became cleaning the floors, tables, and bathrooms after that point. I lasted three weeks and just quit showing up.