I have been proselytizing Bitcoin since 2010 and wanted to ask the community to critique and help me fine-tune what is essentially my sales technique for selling folks on Bitcoin.
When I discuss Bitcoin, people tend to get a little perturbed and start saying "well how is it worth anything!?". At this point I begin using the analogy that Bitcoin's value comes from utility, adoption, and scarcity. Utility is obvious - you can buy almost anything with BTC that you can with USD (and in some cases more). Adoption is also not difficult to convey. Scarcity has always been the sticking point.
I started using an analogy (in combination with describing the halving blocks and "designed scarcity" of the system) that Bitcoin does in fact have a gold standard: energy. This "gold standard" is superior to actual allegedly-gold-backed currencies in that it cannot be divorced from utilizing energy for production. Because mining is required to find blocks/solve equations, you are also implementing scarce man-made tools (GPUs/ASICs) to mine bitcoin from the scarce inputs (electricity).
I have taken it further at times and described that Bitcoin is truly a modern currency due to using the collective knowledge of all of mankind (the microprocessor, etc) to create a store of value. People tend to like this angle - it sounds epic and intriguing

Hack away! I want to have as close to an unindictable spiel as possible when talking to people who really know their stuff regarding currency/forex/economics.