The light switch of my bathroom had been broken and I want to replace it with elegant design switch for it. I have read about the switch today because I was wondering how it is operated. A switch is made for opening and closing something most basically the light. At infinite resistance, no current flows and no power is dissipated. At zero resistance, there is no voltage drop and no power is dissipated. When the switch changes state however, there is a brief instant of partial contact when resistance is neither zero nor infinite and power is dissipated. During that transition the contacts heat up. If the heating is excessive, the contacts can be damaged or even weld themselves closed.
There are switches that can have electrical ground especially when the switch is in the bathroom. It can be wet sometime that cause electrical flow so if pushed, you will have an electrical shock. To make a safe switching, choose switch that are durable and safe. If you do not know anything about it then ask for assistance in the store so they will help you though some may be pricey but safe.