Is my apartment's floor and walls considered "ground"?

Yes and no.

Not really, no, when it comes to any useful behavior you would expect from a "ground". You could not put a lightbulb between "hot" and your floor and expect it to light up. Not enough current could flow. If you had a big enough sheet of metal to lay on a wet floor and wired it to your bulb, maybe.

Yes, when it comes to shocks and personal safety. It takes much less current to produce a painful or even dangerous shock than to light a bulb. Bare feet on linoleum tile, or probably just about any flooring, is plenty adequate grounding to produce an unpleasant shock.

 

Yes and no.

Not really, no, when it comes to any useful behavior you would expect from a "ground". You could not put a lightbulb between "hot" and your floor and expect it to light up. Not enough current could flow. If you had a big enough sheet of metal to lay on a wet floor and wired it to your bulb, maybe.

Yes, when it comes to shocks and personal safety. It takes much less current to produce a painful or even dangerous shock than to light a bulb. Bare feet on linoleum tile, or probably just about any flooring, is plenty adequate grounding to produce an unpleasant shock.

Bare feet on a tile floor on a concrete slab on the ground allowed me to get a really exciting shock years ago. There was a damaged wire shorting to a non-grounded steel electrical box with a stainless switch plate, and I was barefoot.
But a cheap tile over wood floor is not much of a ground at all and I do not think you would be zapped. BUT DO NOT TRY IT!!! "Your experience may differ."

 

Bare feet on a tile floor on a concrete slab on the ground allowed me to get a really exciting shock years ago. There was a damaged wire shorting to a non-grounded steel electrical box with a stainless switch plate, and I was barefoot.
But a cheap tile over wood floor is not much of a ground at all and I do not think you would be zapped. BUT DO NOT TRY IT!!! "Your experience may differ."

I think you’re usually grounded well enough - maybe just through the air - to at least feel a hot wire. It doesn’t take much more to make it unpleasant.

 

If I walk under HV transmission towers while holding a metal staff I can feel tingling sensation in my arm.
Yet, I am in no way directly connected to the HV cables 50m overhead.

(I don't suggest that you try this experiment.)