…is clearly expectation.
Let go of the idea that an experience has to be exactly how you pictured it. If you plan out every possibility and have that expectation in your mind, by definition the experience will not live up to that expectation. Maybe it will even be better, but not if you’re focused on the fact that it didn’t meet your expectation.
Open your mind, open your heart, open yourself to an experience. To the extent that you can’t stop yourself from building this rickety scaffolding of expectations, try to just allow that to be a passing thought, an observation. Try not to let it color the situation.