Modern US plugs have a wide blade for “neutral” or “return path” and a narrow blade for “live” or “hot” (plus the round ground pin). In my part of the US, we only have GFCI near water (restrooms and kitchen) but always proper circuit breakers and ground to water pipes where the mains AC enters. There still exist many 2-prong appliances, but those will never have the case connected electrically!
If you don’t have a proper earth ground, then tying anything together is bad news. You could have one appliance shorting out and damaging others on the same circuit, or burning your wires in the wall. Regarding the PC switch-mode supply, AC in goes to a transformer which doesn’t care if hot and neutral are swapped.
Sorry if I sounded like a jerk. I’ve been working on PCs and appliances for decades and only once ever had an energized case; not a PC. Touching two machines each plugged into a seperate circuit, got a metallic taste in my mouth, pulled out the meter and measured ~80VAC! Verified my vending machine and outlet were wired correctly and recommended getting their popcorn machine and outlet checked out.
