Today Stephen Stills's Love The One You're With popped up on my MP3 player. I couldn't say how many times I've heard this song since it was first released, but today was the first time that it ever occurred to me that the "Do de do do do do de do do" part of the chorus is the same as that found in Suite:Judy Blue Eyes.
Now I've regarded LTOYW as a celebration of promiscuity; a legacy of the hippy free love ideal. But inserting a fragment of SJBE gives it a completely different meaning
SJBE paints a fractious love affair, but through recycling that scrap it appears to me that Stills is really sticking it to Judy Collins. I'd make a guess that she believed in monogamy and arguments over this was a big factor in their break up.
But on the other hand he may have just thought it was a catchy hook and if it worked once...