It wasn't just in the Pet Sounds/Smile era that the Beach Boys were harmonic innovators. Two of their earlier signature songs have well-placed chord twists that give them their distinct emotional color: one blue, the other sunny.
The first is the unutterably sad "In My Room," which we may hear now in hindsight as Brian Wilson's depressive mission statement but which still packs a melancholic punch without any knowledge of its author's psychological profile (listen to the Langley Schools version, for instance). The harmony seems bone simple and the melody plain, but I'd point to two quirks that make this gently rocking 6/8 lullaby ache the way it does. The song is the key of B, and there aren't a lot of chords here, but the second one we get is wholly counter-intuitive and pretty haunting. The melody starts out by clinging, childlike, to notes of the major triad, B, D#, and F#:
Thoughout all this the harmony thrums brightly on the B chord, except for two beats in measure 3, when it moves not to E, as it "should," but to an A--a downward move that beautifully conveys the singer's wallflower reticence, not to mention creates an attenuated major-seventh harmony:
This I-VII progression soon becomes the song's ambling vamp. The other note I'd make here is that the way "in my room" is phrased from the start is exceedingly shy and retiring--"in my" are pickup notes, "room" is on the downbeat over a C# minor...and there's no more new information, except a lovely VII-V turnaround in the underlying chords, for about two bars. That's a pretty gaping emptiness at the heart of this heartbreaker.
The other song, in a totally different color, is one that's always unaccountably moved me, "Don't Worry, Baby." No, it's not because I've since learned that drag racing, or even "chicken," is apparently the song's dramatic backdrop; I thought it was probably just my weakness for yearny vocal harmonies (blame the Stand by Me soundtrack, but this is one of my favorite songs and I can't be talked out of it). Upon examination, though, what makes "Don't Worry, Baby" pop is another good old-fashioned chorus lift. We're resolutely in the key of E for the verse; then at ii-V turnaround, we lift subtly into the iii-VI, and the sudden A# note in the melody cues us that we're sliding into a new key:
The only quibble I have with the craft here is that the songwriters (Wilson and Roger Christian) haven't figured out a graceful way to get back to the home key, so we get this little bit of harmonic housekeeping tucked in there:
That's easy to forgive, though, when the overall effect is so transporting.