J2B...'Chuffed' is one of these peculiar 'Janus' words in that - at one time - it meant both pleased/satisfied and displeased/disgruntled! It was used in both ways as military slang in modern times. However, the basic word 'chuff' as an adjective dating from the early 17th century meant 'puffed/chubby', so the connection with the 'pleased' meaning is probably just the idea of being puffed-up = self-satisfied. The 'displeased' meaning is connected with the Kentish dialect adjective 'chuff/choff' meaning churlish/morose. Nowadays, of course, 'chuffed' is generally used only to mean pleased...I can't answer for Kent, of course!