Farming
The basic idea is that you don’t (have to) farm at all, which explains the lengths ANet has gone to to prevent classing farming situations known from other games. They are constantly at odds though with some player’s desire to keep to habits grown in other games to farm for whatever they’re looking after at the moment.
Personally, I hate farming but find that pretty much everything I need tends to accumulate by itself in this game anyway (including karka shells if you run around Southsun occasionally and kill the odd Karka Queen). ANet actually did a pretty good job with the loot system in that you do get a variety of items if you just play a variety of content, much more so than in other MMOs I played.
Nevertheless ANet does seem to listen to many people, including those that feel a compulsion to farm for specific materials rather than just let it accumulate by itself. As such they’re introducing the map reward system with HoT which gives you the chance to gain specific materials by playing a certain zone (materials available changing on a weekly basis). I’m really looking forward to see how their inital take on the system has involved in BWE3, it does look promising.