Of course in terms of general travel experiences, rather than hotel experiences, here are a few I could mention -

Arriving at dawn at the Fisherman's Cove Hotel in the Seychelles and seeing my first tropical beach. I've never forgotten it, I can still hear it and smell it, and it changed my life. Bora Bora, Isle of Pines etc all came later.

Seeing the ruins of Leptis Magna in 1981 and Angkor in 1992 and having them virtually to myself.

Landfalls on Pitcairn Island and Tristan da Cunha.

My first *** Michelin meal at the Oustau de Baumaniere in Provence (it was Gigot d'agneau en croute in case you're asking).

I learned to drive relatively late in life and the first time I ever took my wife out for a drive was in Tonga. That was pretty 'wow!'