I did it once. Went to Alinea in Chicago. $400/person before wine pairing to give you a gist of the scale. At that level the experience transcends the food. It's all-encompassing. You don't worry about the valet, the restaurant has that covered. You don't worry about your coats; they take them for you. You don't get a jacket ticket.
It almost feels like the servers have ESP. They get you a new napkin, or fork before you even raise your finger (but not after you thought about asking). The food is timed perfectly. Once everyone finishes the course, the next course comes. If there's a conversation about the previous course, the next one miraculously waits until that conversation dies down.
The food is ordered in a way to activate taste buds. It's not just from "lighter fare" to "heavier fare." Salty/sweet, temperature play, texture play; it's all on the table and masterfully executed. There's introspective dishes served in one course, and fun dishes (like candied balloons) in the next.
The food itself is nutrient-complete, so while the portions are ostensibly small, you leave satisfied, and each course builds the hype. There's never a dish that ends up making the last feel "smaller."
You can sit for as long as you want, then when the group decides it's time to leave, the restaurant already has your jackets ready, the car is ready, and everything is in it's right spot. There's no mix ups.
The crispness of the experience made me realize food can be more than just a meal, but ultimately it's hard to define without trying it.