When you test an idea, ask people what they do about the problem today. Not whether they'd use your product.
People are kind about ideas. What they already spend time or money on is much harder to fake.
That's the core of The Mom Test by @robfitz.
Around 1990, wireless networks ran at one to two Mbps. A CSIRO team led by John O'Sullivan aimed for 100.
Part of the fix came from radio astronomy. His old group hunted for pulses from exploding black holes, and the same kind of maths cleaned up signals bouncing off walls.