Make Friends, Make Friends
(never, never break friends/if you do/you'll catch the flu/and that will be the end of you.)

So we all know this one, but interestingly enough, the popular comedian Adam Bloom genuinely believes he invented this rhyme, in a playground in Richmond in 1977. No one else knew it before he invented it, and he will accept no argument to the contrary.
written by Su*an T*bacc*, approved by Susan

In girl scouts, we had a song that went "Make new friends but keep the old; one is silver and the other is gold." which we promptly adapted to "Kick new friends but pee on the old; one is slimy and the other is mould." Don't ask.
written by Ab*y Nor*al, approved by Mansh