Usually when electronic devices have a metal housing, they're tied to ground. Getting shocked could be a sign of a wiring issue in the building. Ground should be at zero electrical potential.
The tingling comes from some leakage across the transformer isolated primary/secondary but is so small that it’s not dangerous.
That’s also completely unrelated to static discharges that zap you once you touch something that can equalize the potential
The US extension cable is earthed, and I believe some duckheads in other countries are as well. The power adapters that were in use for mac desktops during the time period that the person I am replying to was referring to were earthed. https://th.bing.com/th/id/OIP.vmVNrqGAR3raMcey5fAXUQHaE6
Although you are correct in cases where the device is not earthed.