Ask HN: What's your greatest non-tech hack?

Of course this is inspired by the question from the application for YC but I'm not applying this year and I'm genuinely interested in sharing and hearing some other great anecdotes.

For me, I think it was when I used social engineering to track down the programmers who designed a very expensive product for a vendor in my industry and then negotiated a price to build the same full featured product for 1/5th of what the vendor charges for a one-off job. They were freelancing on odesk/elance and I had used the demos that vendors offer of their products to categorize the features and estimate what technologies were involved. When I talked with the programmer he admitted about how much he was paid for work on their product.

The industry is e-discovery for law firms, btw.