So what's the magical number that you think people should be undercutting by? 5 gil? 10? 100? The entire point of undercutting is to get your item to be the first on the list to attract the maximum potential buyers. Undercutting by 1 gil isn't being spiteful, it's business plain and simple. Personally, I usually undercut rounded down to the next 5 gil unless the item is less than 100 gil then I'm a 1 gil undercutter.