British actress Sally Hawkins plays what seems to be the happiest woman on earth in Mike Leigh’s comedy “Happy-Go-Lucky”, about a north London primary school teacher named Poppy who seems able to take every problem thrown at her in stride. Always smiling, always laughing, she lights up the screen and the gloomy world she lives in. The epitome of effervescence, she’s an irrepressibly optimistic 30-year-old woman with a contagious smile who tries to brighten up everyone who enters her orbit.

After spending two hours watching Hawkins, as Poppy, find the silver lining in every cloud, see every glass as half-full rather than half empty, and doing her best to coax a smile out of every crotchety, grumpy or surly soul she encountered, I was wondering: Is this person for real? Can anyone really be that happy all the time? As a natural-born pessimist weaned on scepticism and sarcasm, I’m a professional cynic incapable of overlooking the flaws in anything. So how can anyone be that happy?

So — and this is one of the best parts of covering film festivals like the Berlinale — I got the chance to ask Hawkins just a few minutes after the curtain went down: “Are you really such a bubbly, happy and optimistic person or are you just a good actress?”

“It’s all acting,” said Hawkins. “I’m a nightmare.”

But then she cracked up laughing before she added: “I guess I’m naturally optimistic as a person but Poppy is at another level. She’s all-embracing to everyone, she doesn’t give herself a hard time for anything. I hope I can take that with me, her incredible energy. I just couldn’t be tired or a bit down playing her. She was a joy to play.”

It was also a joy to watch her taking on all the mean, irritable, frustrated, unhappy and angry people. Even all the mean, irritable, frustrated, unhappy and angry journalists in the audience walked out with a smile.