I mystery shop chain coffee shops in the UK. I don’t get paid but I get the food for free. I do it on my lunch break and complete the 20 min report on my train ride home.
I am required to pretend to have an allergy and measure how seriously staff treat it. I am always honest about this and note down any instances where the wrong milk for example is served.
The rest of it, such as customer service I give them all glowing reviews. The idea that a overworked underpaid barista should be giving me welcoming and friendly comments with a smile on their face is patronising and insulting. 5 stars across the board.