Rumours is a great album for many reasons. One of them being that it's an album about troubled relationships sung by people who are going through some serious relationship troubles themselves - Wikipedia:
At the time, Fleetwood Mac's line-up consisted of guitarist and vocalist Lindsey Buckingham, drummer Mick Fleetwood, keyboardist and vocalist Christine McVie, bassist John McVie, and vocalist Stevie Nicks. After six months of non-stop touring, the McVies divorced, ending nearly eight years of marriage. The couple stopped talking to each other socially and discussed only musical matters. Buckingham and Nicks—who had joined the band before 1975's Fleetwood Mac and after guitarist Bob Welch had left—were having an on/off relationship that led them to fight often. The duo's arguments stopped only when they worked on songs together. Fleetwood faced domestic problems of his own after discovering that his wife Jenny, mother of his two children, had an affair with his best friend.So basically, everyone hated each other, but they managed to make one of the greatest albums of the 70s. Then we have Mr. Timberlake. He's cool, I guess. I wish he'd stop messing around in Hollywood and put out another great pop record. His song is also a bitter farewell to an ex-lover. I'll let someone else dissect the thematic interplay between the two songs.
Fleetwood Mac - Dreams
Justin Timberlake - What Goes Around... Comes Around