I love my coffee and drink a lot of it, but I would never accept the offer of a coffee if I knew in advance it was instant coffee, I would rather have water. Instant to me isn't coffee, it's hot water with a very vague but quite unpleasant coffee-ish flavour. The last time I was offered a coffee and only after having it my hand realised it was instant coffee (was 18 months ago), I just waited till my host went to open the door to the postman and I poured it down the sink. If I had known it was instant I could have saved wastage by having a glass of water instead.
Orange juice is juice, not Robinson's orange syrup diluted with water, though I like them both, I wouldn't refer to diluting orange as orange juice.
Mashed potatoes are cooked potatoes mashed with butter and or milk, not that SMASH stuff (dehydrated potato mixed with boiling water) that was around the 70s. I wouldn't refer to SMASH as mashed potatoes.
If people want to serve instant coffee, it's fine by me, just tell me it's instant so I can choose a glass of water instead.
Are there any other countries in the world, apart from the UK, where this post could even exist? Every other country I have visited, you would never be given instant coffee when offered coffee.