There are some laws that even Hong Kong taxi drivers cannot break. One of the is the law of inertia: you learnt this one in science at school. Bodies move in the direction of their momentum unless acted upon by an exterior force. So if you are inside a taxi that is rapidly moving forwards, and the driver suddenly brakes, your body will continue to move forward until stopped by either the seat belt or the windscreen. This leads to the next law. Rapid stopping and starting will inevitably lead to nausea.

These two laws cannot be broken, despite many a taxi driver's best efforts.