Letting is the hard part. Plenty of people want to be surprised and then take over the planning, checking the restaurant reviews, suggesting a better route, improving the gift into something they would have chosen themselves.
Being surprised means ceding control, which for organised people is genuinely uncomfortable. You have to accept a slightly worse plan, executed by somebody who is trying.
The delight was never really in the plan. It is in the evidence that somebody spent a Tuesday afternoon thinking about you.
Next time something is arranged for you, don't ask what it is. Just get in the car.