I know men and women like Happy-Go-Lucky's Poppy. They work for my division: sinister optimists who would use emoticons in conversation if possible. Their commitment to operational and institutional clichés isn't calculated to toady up to their bosses; these people genuinely believe that everyone should have a great day, that anyone can be a leader, and there isn't a problem for which discussion wouldn't serve as the best cure.

Poppy isn't this delusional. Writer-director Mike Leigh creates a woman who surprises us (and herself) every few minutes. Most of the reviews don't suggest her complexity. For one, she's no airhead; in a conversation with her pregnant sister she makes an okay joke about five-year plans that references Joseph Stalin, and breezily dismisses a tome on unified physics*. She uses cheerfulness to keep her distance from people who don't deserve a second look. The ones she likes -- her roommate, the child in her classroom with family problems, the hunky, knob-chinned social worker who becomes her boyfriend -- don't get the fluted, nervous chuckle and aren't pummelled by her inclination to always get the last word. The much-praised confrontation between Poppy and the bum strikes a false note: it's the one time that I thought Sally Hawkins was too self-possessed to risk her safety.

Otherwise, Happy-Go-Lucky is one of my favorite Leigh films: crisp and light on its feet. Erotic too: a post-coital conversation on a balcony between Poppy and the social worker, simply and beautifully captured in long shot with the actors' backs to the camera, bridges the distance between Poppy's attitude towards the world and how different striking poses seems when you've spent the night with someone with whom you might fall in love.

*EDIT: A reader who knows more about unified field theory than Alfred Soto suggested that I correct this line. I thank him.