Early Mickey cartoons were weird man. But usually good weird. And The Barn Dance is good weird. I think of it as a romcom, instead of the usual adventure or good vs evil stories we see Mickey in. Mickey himself is so different here. He loses, for one. He's a lot more vulnerable too. Do you ever see him cry like this? Well okay his crying was humorous here, but the idea is still novel.
Personally this cartoon is one of my favorites, mainly because it's so different. It's nice to see this "hopeless lover" take on Mickey. And Pete as a polite rival who wins Minnie over is a nice change of pace from the bully or the kidnapper role he usually plays.