Can a cop pull you over walking home asking why you are out so late?

Sure they can. It happened to me a few years ago.

Uhm, just as a note: Europe, not US.

I told them I was in the office. They asked if I'd been drinking. I told them I was just too tired to park properly and wanted to go to bed. They kept asking dumb questions about my job (I was so tired I’m pretty sure I was really confusing), so they gave me a breathalyzer test, and then let me go once they understood they were just bothering a poor person working too many hours.

Why are breasts attractive?

I was going back home from my office, around 3 or 4 am. Huge project to hand in, I just kept on going until I had it finished and polished, and when I finally managed to finish I drove back and started looking for a parking spot.

That's when the policemen spotted me: I was so tired I was unable to park where I found a spot, and just drove to the next one I found. When I left my car, they pulled me over and asked me a bunch of questions (the usual ones, like where I was going, where I was earlier, etc).

I was polite throughout the whole interaction, there wasn't much they could do. They weren't nice until it was clear I was just tired and not DUI, but that makes some sense.

‘We tried and it didn’t work out’: CDPR co-founder says it shouldn’t stray from AAA open-world RPGs - Video Games Chronicle