Here's a story about WoW being WoW.
Last summer I decided to get the Staff of Immaculate Recovery (http://www.wowhead.com/item=32344/staff-of-immaculate-recovery
) for my priest. I spent 2 months visiting the Black Temple and killing Gurtogg Bloodboil over and over again. I did get the staff in the end, but about 75% of the time I kept getting "this worthless cloth chest thing that I won't ever use" (http://www.wowhead.com/item=32340/garments-of-temperance
Recently I decided that I want to get the recoloured Absolution Regalia set for transmog purposes and I come to find out that "that cloth chest thing" is a part of the set. So I go to the Black Temple once again. Now I've been there twice so far on my quest for the set and guess what dropped off Gurtogg BOTH TIMES I've killed him. That's right, the bloody staff I spent two months grinding for last summer!