At first glace to the untrained eye, Liam Hemsworth's mouth looks as if he's trying to squeeze out a smile at the Australian Academy of Cinema and Television Arts Awards. If you look carefully though, you'll notice his "mustache area" is slightly tensed and his upper lip is mildly stretched and thinned as well. Hemsworth's nostrils are flared too. His eyelids are partially closed, but not in the sincere smile manner. If his lids were closed as a result of a true, felt smile - we would see the classic, concave-down furrow nonverbal sign in Hemsworth's lower lids (see Secret #921: Spotting Giants' Sincerity). This young actor is not smiling sincerely at all, moreover his attempt at a social smile is also poor. Liam's emotions are disgust (best exemplified by his flared nostrils) and anger (his out-of-context Clint Eastwood-like eyelid squint as well as his thinned upper lip).
Anyone can spot severe anger or disgust. How skilled are you at picking out moderate or subtle examples? Miss them at your own risk.