I worked for many many years in what I suppose most would consider very top end/hugely wealthy hospitality, both private and business.
For the large part, established, Old money British families with properties were a joy to work with, often eccentric and entertaining and unfailingly polite and courteous. Not at all flashy.
Then the supremely rich Saudi/royalty who are quite the reverse: overtly extravagant, materialistic, exceptionally demanding on a 24 hour basis. The females would shop by day and be rarely seen by night, the men would unlikely surface before mud afternoon but be up all night with butlers catering t every weird and wonderful whim... would be loyal to regular staff (one even funded private cancer treatment for their uk driver).... But daily /hourly demands are common and very much expected.
Then there's the insanely rich Russians- often very visibly uncomfortable in their own skin, hugely competitive, desperate to be seen to "own" the things they perceive to be signs of wealth/success. Tetchy and often need to be on the move so may have an entire floor of an hotel but often utilise it for a fraction of their time, flitting between Switzerland or similar...
Sports significant figures with billionaire status were most often unfailingly kind and just appreciated some discretion abd calm.
General theme is that real insane levels come at huge personal costs quite often and I'd often think to myself how I wouldn't be tempted to swap if given the chance.