Every meeting that is spent in a meeting room has costs associated with it. Starting from the electricity you use in the meeting room, to tele-conference calls, wages of people involved in the meetings to the impact of the decisions that come as a result of the meeting. The key costs are money, time and emotions.
Hard to measure the cost of emotions while in a meeting room, but it is easy to measure the cost in terms of time and money. So while you are in a meeting room, remember to make the meetings most cost effective by having clear cut objectives and using yours and other person's time more efficiently.