What grinds mine is when i list things on the AH and then Mr. Coolstuff over here undercuts it by 3k. Look you inexperienced goblin, undercut by a single gold not 3k. People will go for your items even if its just 1 gold under. If everyone undercuts by 3k ya gonna make the items worth less than dirt. Who wins then? The customer thats who and that ain't good business!

TLDR:So please for the love of Gold undercut by a single gold piece and don't sink an entire items worth because as soon u do everyone else undercuts you and then it cascades.