Business class is weird - there is a real thrill if you have never done it before, but if you analyse it the thrill doesn't quite make sense.
Eg: sitting in the business lounge with free champagne feels special because it's way nicer than being crammed into a row of seats in the main terminal with no free drink..
But in real life, you could buy a bottle of champagne and sit somewhere much more lovely any day of the week, at a fraction of the price!
Similarly, eating off real plates, with real little knives and forks, real, reasonably pleasant food feels amazing compared to waiting for your processed, packaged plastic tray...
But you do this every day of your life outside an airport. 
Lying flat feels like an incredible treat because it takes away the pain of trying to sleep upright with some random drooling on you...
But we get to do that in a much more comfy bed every other day.
So it's a joy by comparison. There is also an instinctive, status driven joy of knowing you are getting better treatment than people 2 metres away. (Not nice to acknowledge but true).
Basically, You spend the flight feeling lucky and special.
As a one off it is great fun, and if you do it, make sure you turn up early so you can enjoy the business lounge.
However, as an actual luxury, you can spoil yourself way better, for way longer, with numerous other ways of spending your money.