You are sitting at a table outside a restaurant in a city you do not live in, eating something you could probably find at home - pasta, fish, bread, a salad of some kind. It tastes, without question, better. You mention this. Everyone at the table agrees. No one fully explains it.
The ingredients are not obviously superior. The pasta is pasta. The olive oil might be slightly better, or you might just believe it is because of where you are and what it cost to get there. The bread is different, but bread is always different, and you do not usually notice.
A significant part of what is happening is in the eating rather than the food. At home, meals tend to be functional events with competing attentions - the email that needs a reply, the programme you are half-watching, the thing you forgot to do this afternoon. On holiday, the meal is the thing. You are fully present to it, or closer to fully present than you typically manage. The food gets your full attention, possibly for the first time in months.
There is also the effect of context on sensory experience, which is more powerful than most people credit. Studies have shown that identical wines are rated higher when served in heavier glasses, in nicer rooms, at higher prices. The rating is not dishonest - the perception genuinely changes based on the surrounding information. Your brain uses context as evidence. You are sitting outside in warm air with people you like and no immediate obligations. The context is excellent. The brain upgrades the food accordingly.
Hunger is also a factor that tends to be overlooked. Holidays often involve more walking, more activity, more time between meals. You arrive at lunch having spent a morning doing something. The food tastes better partly because you are actually hungry, which is not a state you regularly achieve at home, where food is available within forty steps in any direction at any hour.
The honest answer is that the food is not better. The eating is better. And those are not the same thing, but the brain cannot always tell them apart, and it is not clear that it matters whether it can.
Disagree? Say so.
Genuine pushback is welcome. Personal abuse is not.