The best casino experience that I will never forget is when I had a nice winning session in blackjack, walking out with $11K, having started with $300.
A night I will remember for the rest of my life, the night I lost $2,700.
And what's worse is that some of that money wasn't mine. It was a long time ago, I was young and irresponsible. It was a lesson that cost me dearly, but I've learned it forever.
For me, the most memorable casino experience would probably be one where I was with good friends and everyone was just enjoying the atmosphere. I think the people you share the experience with often make it more memorable than the amount you win or lose.