Without fail. your trip will not go perfectly. A hotel will lose your reservation. The museum you want to see will be closed for renovations. You won’t find that “perfect” paella. Rather than wallowing in self-pity and complaining about those “failures,” mange your expectations, expect a few things to go wrong and make the best of the situations.
Ask the hotel if they will give you a deal on a room. Use that free afternoon to check out another museum or exhibit. Buy all the ingredients for a great paella at the local markets and do it yourself.
Inevitably, things will go wrong. It’s up to you to keep feeling right.