Moral Event Horizon: John, George, and Ringo arguably crossed this when they take Faul to India to try and transfer the real Paul's soul into Faul's body, doing so will cause Faul's soul to cease to exist. This doesn't work, luckily.
Wangst: John, seriously? We know Paul was your friend, but your quest to include references to his death in everything you do from that point on starts to look a bit obsessive. You've got to let it go.
The Woobie: William Campbell eventually (and possibly inadvertently) becomes one of these; we're clearly supposed to view him as a ruthless, imbecilic and opportunistic interloper, but when you think about it he gives up his entire life to take Paul's place, not only to save the band but also to spare the millions of people who will apparently commit suicide upon hearing of Paul's death, only to be constantly bombarded with mean-spirited digs and references to how he's not the real Paul and how the real Paul was so much better. You can't help but feel a bit sorry for him.