peccadillo

peccadillo \peck-uh-DIL-oh\, noun:

A slight offense; a petty fault.

No peccadillo is too trivial: we learn that the mogul once blew his top because his laundry came back starched (" 'Fluff and fold!' he screamed").
-- Eric P. Nash, "High Concept", New York Times, May 10, 1998

And besides "what do they say? 'Don't judge lest you be judged.' Everybody has their peccadilloes."
-- "Tyson has a friend in his corner", Irish Times, October 21, 1999

Child of a dominant mother, victim of a guilt-ridden conscience, [St. Augustine] wrote bewilderingly haunted 'Confessions,' in which infantile peccadilloes like stealing apples and adolescent fumblings with instinctive sexuality are bewailed with all the anguish of a frustrated perfectionist.
-- Geoffrey Parker, "True Believers", New York Times, June 29, 1997

Peccadillo comes from Spanish pecadillo, "little sin," diminutive of pecado, "sin," from Latin peccatum, from peccare, "to make a mistake, to err, to sin." It is related to impeccable, "without flaw or fault."