Eh. The Undertaker vs. Dudleys match that "killed off" Paul Bearer by burying him in concrete oatmeal was honestly the most soul sucking thing I've ever watched in a main event.
Actually thinking about it, Undertaker has had quite a few dreadful PPV duds, but I tend to think a good chunk of that is he tended to get stuck with gimmick workers, or weird match stipulations. Plus he's been on a billion PPV's, so I suppose it is inevitable.