Ever wondered about the difference between the Dandy & the Gentleman? This quote explains it all:
A gentleman is cultured to the point of refinement, but a dandy is cultured to the point of decadence. To alleviate his boredom, he will often grow overstated, perverse, toying with vulgarity. Responsibility to no one other than himself is a central tenet of the dandy charter!
Being consistently well-mannered is far too bourgeois for the dandy: he holds to the more aristocratic character, in that he often feels himself above such workaday concerns as manners and accountability. In order to avoid being thought banal or trite, he becomes impossible to predict: tender and kind one moment, cold and cruel the next. He has transcended any dowdy middle-class notions of what ‘refinement’ is. There are good reasons why the dandy was reviled: he was a self-absorbed, egotistical, useless prick. Nineteenth century books are rife with this dandy vs. gentleman distinction, even having adjoining pictures of each species for clarification.
This quote is from The Dandy as Libertine which I found via Soul Sphincter whose post The Grand Budapest Hotel: Triumph of the Dandy is well worth reading.