Groceries? I walk. Have one option a 15-minute walk away, and two 25-minute walks away. I do 3 to 4 bags at a time, not a problem. I also have subway/bus literally across the street, and right next to highway for when driving to clients makes sense -- but usually can get to them via mass transit (subway and bus) so long as they're in certain areas within about 20 miles (32km) from where I live.
Still own a car, but it's only for fun, not necessity and I never use it for errands. If it wasn't for fun, I'd not bother with owning one.
I live in Boston. It snows here and I do often buy more than one bag of groceries at a time. Fortunately, I just walk two blocks down the street and go into one of the two grocery stores that are right there.
Compare where I grew up in southern NH: it snows there, too, but the nearest grocery store was a 20 minute drive, so of course I would drive there. Rural NH is not a city, though.
I was only there for the Superbowl and never actually walked one, so maybe it's not so convenient.
What's the big deal?
The problem is that personal car ownership with our current technology does not scale up, when taking into account of environmental impact. Nor when you reflect on just how much public right of way we've given up to infrastructure for cars. Nor when you think of how many people die of automobile accidents. Nor or the impact cars have on living in social communities.