Discharge the static buildup on your body safely before touching a conductive object like a metal doorknob.

Before touching a metal object you suspect might give you a shock, touch a less conductive surface first, like a painted wall or a wooden door.
Alternatively, hold a metal object you are already carrying (like your keys or a coin) and touch that object to the doorknob or metal surface first. The static charge will discharge through the key/coin, often without you feeling the shock, or with a much smaller spark at the key.

N/A - A simple behavioral trick to safely dissipate built-up charge.

Ground Yourself Before Touching Metal