Edie Brickell - What I Am Its just so simple its funny.
Also to mellow me out, I usually like classical. Beethoven, Bach, or Mozart. Some others, but not as much.
Also not sure who originated, but I usually seem to smile when I hear (Disneys') Its a Small World. and other Disney songs.
By chance I listen to just about all music,(all forms of rock, some rap, classical, movie soundtracks, very light on Jazz, etc..) the least I listen to is country. But even there I find quite a few good songs. Particulary older country, like Alabama, Charlie Daniels, Willie Nelson, Boz Scaggs, etc...
There are also a lot of one hit wonders that do it for me as well.
They had a couple of hits, but Hot Chocolate-You Sexy Thing, ABBA-Super Trooper (puts a smile on) KC and the Sunshine Band-Please Don't Go, Bay City Rollers-Saturday Night......
Also a lot of Bee Gees work for me.....