So let me say this: Will Ferrell is fantastic in this movie. Really. He's tremendous. I was extremely impressed. Little Biggie (Christopher Wallace) is also quite good, as are basically all the other actors in this movie, except for Michael Pena. It might not be Pena's fault though, because his character is also just not very believable or well written, which makes it harder for him. In any case, the acting is excellent, and generates, for the most part, a very believable emotional atmosphere. Unfortunately, this is not enough to make the movie good.
The thing is, there's not much narrative. An alcoholic loses his wife and job, and, locked out of his house, settles on his front lawn with all of his worldly possessions, ultimately deciding to sell them. The whole film happens over the three days that his yard sale permit (which permits him to spend so much time on the lawn) is good for. So there's not much action, aside from some interactions with other people, namely, a new neighbor, a random kid around the neighborhood, a girl he knew in high school, and his AA sponsor. Pena, as the AA sponsor, doesn't add much to the movie, aside from some basic plot stuff, but he just isn't all that compelling or interesting, and Pena makes him so wooden that we really can't figure out what his deal is anyhow. The other characters/interactions are interesting, and I suppose one could mine them for truths about the human condition, but they don't entirely hold up. They're so brief that we don't really engage with them strongly enough to make them part of the plot. While I appreciate that the movie doesn't make them overdetermined, or hyperbolize them into epiphanies - basically, that it lets them be generally realistic, if somewhat idealized - it also means that there's not really any development to track. So you get kind of bored. The movie ends without any real sense of what will happen next, or even if anything has changed in a meaningful way. So really, all you get from the whole experience is the atmosphere. And like I said - that's fairly effectively done. But it's not really enough to make the whole thing satisfying.