I'm usually averse to these kinds of lists that seemingly take random information and try and bodge it into a nonsense list, but Cracked.com have an interesting tale on five massive songs that almost weren't.
It's worth a read just as the history of five random big hits, not THE five most massive almost non-hits, or whatever other sites try and drum down your throat.
I was interested most in the genesis of Michael Jackson's mega-hit "Billie Jean". The stories of him being bullied and humiliated by Quincy Jones are legendary, so to find that he was able to salvage a track that Jones was so vehemently opposed to AND make a mega hit out it is quite something.