Earlier today I was perusing the official WoW forums, looking for any new info about our favorite game, when I noticed a particular post. Warla, the player in question, was announcing that they had collected all of the cooking recipes in the game. At first glance, this might not seem like much of an accomplishment, but there are a lot of recipes that are more readily available to one faction or the other, such as Dig Rat Stew. Taking into consideration that Warla is on a PvP server and can't easily do a trade through the neutral auction house, this is actually quite a feat.
I'm not really a perfectionist when it comes to my professions (and I'm definitely not the type who would announce such accomplishments in a public forum), but I have known other people that were. One guy I know is a blacksmith and spent hours researching and tracking down every last pattern that was available to him. The same guy was making a point to complete every single available quest in the game too, so his blacksmithing goal wasn't really his loftiest.