Fwiw most of the ‘classic’ classics listed above I read decades ago. I feel no compunction to go back. But these I do:
Lucky Jim – Kingsley Amis. Probably gets it. Most reread book.
Earthly Powers – Anthony Burgess. Too prolific, needs reappraisal.
The Witsun Weddings – Philip Larkin. It’s a book. Also a classic.
And I dunno
The High Window – Raymond Chandler, or
Bluebeard – Kurt Vonnegut or some
Mid-period Elmore Leonard
Hang on, late entry…
The Goldfinch – Donna Tart. Might actually displace Lucky Jim, disrupting the emergent middle-aged misanthrope white guy theme…