The electric feeling is actually caused by EMI reduction measures: per regulations, a Y2 class capacitor must be connected between live and earth in your laptop's power supply. If you connect your charger to an earthed outlet (like you should), the earth is going to absorb the resulting high-impedance supply. If not, the resulting voltage will be present on your computer's metal chassis, which must be connected to the earth per other regulations on electrical safety. Of course, since the capacitor has a high impedance (reactance, to be precise), no meaningful current can go through it, so the "seemingly mains-voltage" on your chassis isn't dangerous at all (as long as everything is working as intended)