Heh! That's pretty funny actually!

Beach Boys had always made happy records

You think so? Have you ever listened to "Today" or "Pet Sounds"?

yeah, those are my fav Beach Boys records.
but......don't they sound happy ?
Today....had all those sweet, sweet love songs, like Pls Let Me Wonder, She Knows Me (all those in the second side, oooohh...real sweet) and it makes me happy.
Pet Sounds.....ok, a bit more serious here, but still gives me the light, sweet, summery feeling, my fav : That's Not Me and God Only Knows

Well, to me "Today" and "Pet Sounds" are melancholy rather than happy albums. They are both very "sweet" albums, but to me they both have some genuinely sad songs on them.

Ummm......yeah, could call that melancholy, it gives me the type of serene, sweet, happy, hopeful, longing, sunny feeling.

Bob Marley & The Wailers.
Bob's stylings always put me in a good mood, regardless - not sure if this is "pop" but whatever. Beyond this I can't think of another... there are individual songs here and there, but no other artist that has this overall effect on me.