A lot of food and drink service places are appalling quality and fail to meet basic standards, which should be a given for commercially prepared food and drink.
With tea, the water must be freshly boiled to 100 C and if sold in a cafe, must be a tea bag, or leaves in a teapot, with hot water top up available, absolutely not a bag floating in a cup. Milk must be only fresh and semi skimmed as standard.
Hot chocolate must be actually hot - most isn't.
Proper butter must be used for toast, sandwiches etc, unless alternatives are specifically requested for dietary requirements. I've lost count of the number of times nice bread has been ruined by shitty spread.
You say not a lot can go wrong with scampi and chips, but many places don't cook chips properly so they're underdone and some use formed scampi instead of whole tail.
We had a holiday recently where we self catered but ate out a lot and there was something wrong with most of the food I was served, it just wasn't done very well, missing ingredients compared with the menu, margarine instead of butter in a sandwich, undercooked chips and twice I was served overcooked eggs when I asked for them to be lightly done.
I'm no gourmet cook and not particularly fussy, but it is so disappointing to pay restaurant or cafe prices for something that is quite basic that I could have made better myself at home with little effort, or it was no nicer than a standard range supermarket ready meal. I got quite stressed near the end, because I was looking at menus and not wanting to order anything because it was likely to be not very nice.