One song will always put a smile on my face no matter what day i've had...

REM-Shiny happy people

Probably helps that im a fan of them anyway!

it puts a smile on my face as well because i met eileen when the song was out we were putting the finishing touches to st davids hall in cardiff and dexys were playing there and us workers ended up drinking in the bar with dexys.
i also smile at milk inc . walk on water . its when i met o/h

9 to 5-Dolly Parton, reminds me of simpler times lol.
Hard Days Night-The Beatles & California Dreaming-The Beach Boys, many a family party spent dancing too these.
Daddy Cool-Boney M, sheer uplifting song.
Touch Too Much-AC/DC, title says it all really.
C'mon Everybody-Eddie Cochrane (sp).
List is bleeding endless!

Right you said song and I know a song that makes smile...well actually laugh...which is called...........the llama song! Because it's a stupid but funny song!
Ok back to being serious (which is pretty impossible for me but y'know ):
Hey Jude - The Beatles
Christmas songs because...its christmassy hee hee
That Girl by Mcfly
Thunder in my heart by Leo Sayer jumpy cheery song
and many more

The authority song, Greenday
or
Accidentally in Love, Counting crows.

Loads of others but they are fav at the mo.
x