What songs make you feel good?
I have about a hundred of them. "Steal My Sunshine" by LEN, "Runaway Jim" by Phish, "Electric Relaxation" by A Tribe Called Quest, "The Biz" by The Sea and Cake, "Lookin' Out My Back Door" by Creedence Clearwater Revival, "Pride and Joy" by Stevie Ray Vaughn, "I Cried For You" by Sarah Vaughan on Columbia, "Jeepers Creepers" by the Dave Brubeck Quartet, Joey de Francesco's "100 Ways" - I mean, the list goes on for pages.
In the realm of classical music, my number one feel-good piece and just generally a top favorite work of mine is Milhaud's Le boeuf sur le toit (1920). Milhaud, a French composer, had spent some time in Brazil; the score is a giant cocktail of Brazilian street tunes and original melodies. The orchestration is radically colorful, and the piece is a ballet to a Prohibition follies scenario by Jean Cocteau. It modulates through nearly every major and minor key.
Here's Alondra de la Parra conducting the Orchestre de Paris, a really fine performance: