I had always liked this song, but never saw the musicians until recently. :eek:
That dude has some serious sideburns. 
I was watching this video, and my daughter looks over my shoulder and remarked “He looks like a monkey!” 
Mister Blue Sky, by ELO
Nothing feels better than dancing with my 18 month old so really any song that gets her moving has my vote. She isn’t too picky but I can’t argue with her affinity for Best Day of My Life by American Authors.
It was the 70’s, hair was in.
It’s a little fun song and reminds me of days when life seemed easier and more relaxed.
Closer to Free, by the BoDeans.
Peppy. Catchy. Toe-tapping.
Even if it became the theme song for a fairly hackneyed night-time soap opera. (Albeit, one starring Neve Campbell.)
“All I Wanna Do” by Sheryl Crow.
This takes me back to a bright sunny day in the summer of 2000, buying comic books for my little daughter:
Enya - Wild Child (video) - YouTube *
If this song had been around in the summer of 1975, I’d have sung it to the one real love of my life as we lay in the tall grass every evening, waiting for the stars to come out:
*Enya, Wild Child and Flora’s Secret.
Only one Beach Boys so far? I’ll pick “California Girls” but really it is only one of many I could choose.
Avoiding, but not disagreeing with, previous recommends:
25 or 6 to 4–Chicago
Yellow Submarine–The Beatles
Or “Don’t Worry Baby”, possibly one of the most lushly recorded vocal harmonies ever.
Jackie Wilson - “Your Love Has Lifted Me Higher”
I like “Kiss Me” by Sixpence None The Richer.
A great number of suggestions. The Beatles clearly lead the Feel-Good field. Also:
I Feel Fine
Get Back
Hey Jude
Getting Better
Penny Lane
As I look through my own library, horns seem to play a prominent role in many feel-good songs.
I’d say the 80’s is the leading decade for feel-good (edging the 60’s).
And at #1… I’ll put Katrina’s Walking on Sunshine as #1, narrowly edging out the OP’s selections, Spencer Davis’ “Gimme Some Loving” and Jackie Wilson’s “Higher and Higher.”
Some others here. Not necessarily the Ultimate Feel-Good song, but certainly worthy of honorable mentions:
Shout - Isley Brothers (or Otis Day & the Knights!)
Centerfold - J. Geils Band
https://www.youtube.com/watch?v=diYAc7gB-0A - George Michael
One Week - Bare Naked Ladies
MmmBop - Hanson
I Want You Back - Jackson 5
Born to Run - Bruce Springsteen
Blinded by the Light - Mannfred Mann
Little Willy - The Sweet
Feeling Stronger Everyday - Chicago
Can’t Keep it in - Cat Stevens
I Want You to Want Me - Cheap Trick
Surrender - Cheap Trick
Love the one You’re with - Stephen Stills
Thank God I’m a Country Boy - John Denver
I Wanna Rock & Roll All Night - Kiss
Hold My Hand - Hootie & the Blowfish
Time to Change - The Bradys (gasp!)
Take it Easy - Eagles
Call Me Maybe - Carly Rae Jepson
I Get Around - Beach Boys
Scarlet Begonias - Grateful Dead
Ruberband Man - The Spinners
Born to be Alive - Patrick Hernandez
Whenever I Call You Friend - Kenny Loggins & Stevie Nicks
Keep Yourself Alive - Queen
Juliet - LMNT
You are the Sunshine of My Life - Stevie Wonder
Smile - Uncle Kracker
Life is a Highway - Rascal Flats or Tom Cochrane
Think - Aretha Franklin
Freedom - George Michael
You’re the One that I Want - Olivia Newton John & John Travolta
Come Sail Away - Styx
I think if we took a vote Mungo Jerry would be the winner hands down. Especially with that cool video. And speaking of videos here’s one for you. The Videos: If that don’t get you rockin’ you better call the undertaker.