I recently learned "Wild World" by Cat Stevens on guitar. This song makes me feel good when I play it and has some great chord changes. Originally, I thought of this when I read the thread until I realized this is a "la la la" song and not a "na na na" song. lol. But, I'm gonna include it anyway and you can pretend he says "na na na".
"I never dreamed anything could be so soft and fluffy as eating marshmallows on fudge while I lay my head on my Tempurpedic cooling pillow wearing my J.P. Peterman 100% silk double stitched exquisitely striped and stenciled pajama top and bottom." Sorry. I don't know where that came from. Could it be...?