Originally Posted by
Gemina
One player will always be able to cause a wipe. A DPS can mistakenly or deliberately take out the group's healer, paving the way to their doom. A tank can cleave the entire group, or not separate their add from another group's and they're done for. A healer can tunnel vision at a very inopportune time which leads to a player death that snowballs into a DPS check not being met.
Not all, but a ton of wipes can be attributed to single derp from one player that cascades into a giant mess. What is important is to not look at it that way, but rather the group as a whole who could not respond and improvise accordingly when things don't go as planned.