Lots of examples already mentioned sound terrible to me. For myself:
Marvel: Inferno, Onslaught, Heroes Reborn, Clone Saga, Civil War. Hell, pretty much most (if not all) of the major Marvel cross-over events that followed the Mutant Massacre sounded bad to me.
For DC, both the Green Lantern Parallax storyline and all of the reboots following the original Crisis on Infinite Earths.
Marvel: Inferno, Onslaught, Heroes Reborn, Clone Saga, Civil War. Hell, pretty much most (if not all) of the major Marvel cross-over events that followed the Mutant Massacre sounded bad to me.
For DC, both the Green Lantern Parallax storyline and all of the reboots following the original Crisis on Infinite Earths.