When paying for that stronger coffee tastes bitter
When pricing your product, whether good or service, a sense of fairness, good will and customer happiness are created by offering an 'added value' feature at no additional cost for something that takes no more effort nor using any more resources than the 'basic' option. Take that stronger coffee: does your coffee shop charge you more, calling it an 'estra shot', if your cup catches both flows of coffee coming from the grounds-holder? Rarely is a second espresso made at the same time - that extra coffee just flows down the machine's drain. That irks, and my experience could be made so much more happy and rewarding.