The kitchen lighter works on Piezo Electric principle. The lighter contains a Quartz crystal inside it. The crystal is hit by a metal that is loaded by a spring when you press the lighter switch. The quartz crystal when hit by the metal emits high voltage. This high voltage is carried to the tip of the lighter that you see just at the centre. This high voltage induces a spark between the tip and the body of the lighter. If you happen to touch the lighter body while pressing the switch, you tend to get a light shock due to the high voltage it carries.
However, there are instances when the lighter has gone faulty and thus the current leaks through the body. In such cases, you are most likely to get a shock.
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