All the characters in this film are so blandly cheerful that it is actually difficult to dislike them. There's nothing to object to - everything is just so pleasant and amiable. I mean, yes, the camera is static, and the characters uninteresting, and the plots contrived, and the jovial spirit somewhat forced, and the hokey Americananess of it all maybe just too much, and nobody in the world pronounces Iowa like that. But none of this really, truly matters. I mean, if these problems weren't there, the film would be better, obviously. But even with all these problems, the film does still manage to be legitimately entertaining.
I think part of its cleverness is the fact that it never focuses on the one character for to long. It jumps from one bland romance to the next, from a scene about mince meat to a scene about rollercoasters to a scene about pig farming, and it does it all at a fairly quick pace, so though you're never particularly interested in anything that's going on, the movie moves on before you actually become bored. Very little of what is happening is actually important to any of these character's lives - the stakes are rarely particularly high - but this doesn't matter, because it's so pleasant to see a film where the events aren't life or death, where nothing really matters all that much.
And there are some really fun scenes - even if the pronounciation of the word 'Iowa' is frankly insane, the number "All I owe Ioway" is still very good. And the scene where Dick Haymes annoys the ring-toss shyster is pretty great - both because it's cleverly constructed as a scene, and because it works well as wish fulfillment for everyone who has ever paid good money for a ring-toss game (either if they lost, or if they won). And I liked the romance between Blueboy and Esmerelda - two pigs from opposite ends of the sty.
I mentioned before about the static camera, but that honestly doesn't matter all that much either, since the colours of the film are so amazingly lush and beautiful. The colours never make all that much sense in the context of the film. Sometimes it will look like night time, despite the fact that the characters are talking about how it's the middle of the day. Other times an outdoor barn dance will be lit like a Tolouse Lautrec nightclub painting. But this total lack of logic is basically irrelevent, when the colours are this fun to watch.
This isn't a great movie, by any stretch of the imagination. It's barely even a good one. But it is entertaining, and sometimes that's all you want from a movie.