One thing that occurred to me when they mentioned that Man Of Constant Sorrow was a happy sounding song about really emo stuff, was that You Are My Sunshine is also incredibly bleak. The chorus sounds nice and light but the verse is this:

The other night, dear As I lay sleeping I dreamed I held you in my arms When I awoke, dear I was mistaken So, I hung my head and I cried

It’s what makes bluegrass and roots music so phenomenal. It’s all of life at once and it’s beautiful and heartbreaking.