So a friend of yours gets a drop that you need and instead of "giving" it to you, he offers to sell it to you? I'd have to say you're in the wrong. That doesn't really have much to do with manners in my book but more friendship. It's not considered polite to give away high end items to a fellow player, it's nice but shouldn't be expected on any level. The way it seems to me is that you believe that it's something that you would have done if the situation was reversed, but the fact that you say you "woulda" indicates that you have not been in the same situation. Sometimes it's hard to grind for pinks only to feel obligated to hand them over after success if finally achieved; greed is a powerful motivator.