To me, the blues has to be bitter and heartfelt.
@whart I respectfully disagree with this. While the blues started out as a way to express anguish and suffering in the southern United States and can certainly still reflect that, it has morphed over many decades to be much more versatile and translatable to other styles and purpose. Hell, many of the most popular bands in rock are blues based — Stones, Cream, Stevie Ray Vaughan, Led Zeppelin, The Allman Brothers, etc., etc., and a lot of their songs aren’t sad at all. Listen to Keb’ Mo’ — he’s born and raised on the blues in Mississippi and a lot of of his stuff is upbeat while being very blues based while still including songs that represent struggle and hardship. I’d avoid trying to pigeonhole any type of music because really great music and songs, in my opinion, not only lend themselves but almost beg to be stretched and pulled in different directions to see where they can go. I for one enjoy the creativity and variation. But that’s me.