out of capacity that you start to see huge spikes in fees there's not enough for everybody so people start bidding against each other and they start bidding the price of the transaction up that should never happen on a block chain there should be a market but the market is is there to determine how low fees can go not how high they can go and of course from a developer's point of view you don't want to be looking over your shoulder constantly and counting how many transactions your application is making and how many bytes are in each