Think about barbershop quartets. Four assholes. Why are they assholes? Because they are oh-so-strenuously straining to produce a human chord, and oh-so-fucking-proud of the result. They're in love with their own voices, which is pretty damn sad when all they're singing is shit like "Sweet Adeline."
One of the oddest quirks in pop music was that after the vaudeville Barbershop Quartets, there was the Big Band and lounge era; the 40's and 50's, loaded with foursome and fivesome idiots in love with the sound of their own voices. They'd get behind Johnny Mercer or Doris Day and croon oohs, aahs, and repeats of certain words of the chorus. They were, in a word, PESTS.
They also had pesty names, like The Hi-Los, The Pied Pipers, The Merry Macs or The Skip-Jacks. Many a decent vocal by anyone from Frank Sinatra to Patti Page, has been ruined by the intrusive, chummy "harmonizing" by a bunch of drones who make a pleasant old recording sound horribly dated.
Below, two examples. This isn't one of those cruel, effeminate "listen to this, it's so bad it's good" blogs. The cuts below aren't gonna make you laugh. They're presented as historic examples of what is now, in hindsight, a strange phenomena of a bygone age. The Key Notes were professionals and they could sing, but the arrangements were mostly insane. Part of the reason: harmony for the sake of harmony (and ego).
The main thing that distinguishes a rotten "harmony" group is a total lack of interest and empathy for the lyrics. It's all about "DON'T WE SOUND GREAT? ISN'T IT WONDERFUL HOW OUR VOICES HARMONIZE?" So listen to The Key Notes wreck "I Ain't Got Nobody." This is supposed to be a sad, wistful song. Certainly The Mills Brothers and others could get that across, concerned more with emotion and phrasing than harmony. You can easily imagine these smiling as they sing. Whee: "I ain't got nobody…and nobody cares for me…yee-hee-hee!" Yes, they do add that "yee-hee-hee."
Harmony probably goes back to the days of wolf packs. Cavemen would hear a chorus of wolves going off all night long, and grunt, "Hmm, not bad." This led to such strange groups as the "Sons of the Pioneers." What are these guys doing, without women, sitting around a campfire with their arms around each other, crooning about tumbling tumbleweeds, the 69 of bushes?
More recently, there's the incredibly obnoxious King's Singers, who not only seem on the verge of wetting their pants over their own harmonic genius, but make the most ridiculous faces as they gather close together and ooze. I have less problem with mobs of singers who are just making a racket, like The New Christy Minstrels.
When you get down to three people, there's less of a chance that they'll be precocious and precious as they sing together. The Kingston Trio, Peter Paul and Mary and other folk groups were as busy with the message as with the harmonies. Even Crosby, Stills and Nash weren't pretentious (most of the time.) Get down to a harmonizing duo like the Everly Brothers or Simon & Garfunkel and you're pretty much ok.
The Key Notes getting a record deal represents the apex of wrong-headed harmony groups. Mostly back-up groups did their damage on a star's song, not on their own. Who wanted just The Modernaires? Or The Jordanaires? But in the late 50's, cheery and mindless groups, mindful not of lyric but of musical coloring, began to appear on record store shelves.
"I Aint Got Nobody" is followed by "Jada," mostly because you've heard this annoying tune hundreds of times, but probably only as an instrumental. Yes, there are words. And The Key Notes make every one of them excruciating. Again, they're just so full of their own cheery ability to sound like human harmonicas, they forget to be entertaining. Cliff Edwards was able to sing this crappy song without trying your patience. Not this bunch. Following a fey attempt at mimicking old 78's, they lose their minds and happily coo "AH HA HA HA…Ja da! JA DA! DING DING!"
The Key Notes I Ain't Got Nobody - Jada