The bathroom hand drier they invented is/was cool. No heat and knocking the water off with a faster jet of air by pushing it through a smaller hole was a decent improvement.
But their blowers are not just better at drying hands than a standard blower - they are also better at spreading nastiness from people who don’t wash thoroughly. https://arstechnica.com/science/2016/04/dyson-dryers-hurl-60...