Not my very favorite of Muriel Spark's, but the wit is there, nonetheless. The main character is just so unlikeable. (This has been in the diaper bag for ten months, as I've hauled it everywhere, waiting for the chance/desire to read it.)
My favorite passage:
"An old and famous actress had once given her the following advice, 'If you make any excuse make one only. More than one sounds false. None at all is best. It's generally foolish to make excuses and give reasons. Never try to explain yourself to others, it leads to confusion. Avoid psychiatrists.' Annabel had stored up every word, but sometimes she forgot to apply them."