I'm not a Mike Leigh fan. Tangentially descended from the Cassavetes line of filmmakers, Leigh brings that unique brand of quirky humor and working-class angst to the classic style of amorphous plots, semi-improvised dialog, and an emphasis on human interaction over story action. Whether or not you like his films will most likely depend on how much you like his style, because the movies don't offer many other ways into the story.
Given, this can be said of many of the greatest directors ever, most notably Yasujiro Ozu. My recently discovered love of Ozu is a big reason why I'll keep giving Leigh a try. But another big reason is that there are moments in all of his films - and I've seen nearly all of them since this one, his breakthrough work - where sunlight breaks through and his characters are exposed in all their messy beauty. In Life Is Sweet, it happens near the end of the film, when the mother has finally had enough of her troubled daughter's empty life. Their exchange is so honest and heartbreaking that it's instantly recognizable to any parent or child, regardless of how different it is from your own situation.
That's where Leigh shines, finding the parallel humanity regardless of his subject matter. Still, his movies are so intentionally messy and small that I have a hard time sticking with them through their running times. Life Is Sweet is a really good movie, but it's not the kind of movie that gets me excited.