Probably a lack of understanding and being respectful. I don't understand why my wife needs 10 (+?) different pairs of white shoes and while she does not understand why I need multiple pinball machines. We still get along though . I have friends that collect different things; guns, coins, cars, vacations, etc. Some of those things have a high price tag that is over what I am comfortable spending -- but it is their money to spend and not mine.

When someone asks about cost I usually just say "More than you want to know" and leave it at that.