You could add a little melted butter to it.

It's just the UK term for whipping cream.

The HomeRenoVision YouTube channel is a pretty good source of professional information about all stages of construction, and I know they have covered soundproofing, though I think it was mostly walls and ceilings.

Soundproofing is a science. It is more than insulation and foam. Hire a professional to make recommendations. You may be able to diy, or not.

It depends a lot on where you live. I've never owned a car, but I have always lived a short walk from a T stop. It was my primary criteria when apartment and later house hunting. For things like groceries - delivery is pretty common here and I have never felt it to be an obstacle that required a car. You can always rent one for occasional use for a lot less than you might pay to gas, maintain, insure and park it.

New England generally, including its cities, is about the safest part of the country according to crime statistics.

Traveling by train is almost civilized compared to buses or even planes. Yes, things can go wrong, but it's really comfortable so any inconvenience is easier to bear.

The key is waterproof. Those puddles of slush are deeper than you think.

Many neighborhood groups do periodic clean-ups that just take showing up to pick up litter and sweep.

Unless you are trying to get out of the city every weekend, the cost of renting parking (at least a few hundred a month if you fall into something terrific) and maintaining your car is going to vastly exceed what it might cost you to occasionally rent a car. It's just ... silly to pay that much for the possibility that on a whim you can get up and go.

Most of the neighborhoods within the core of Boston have a walkability score of 99. That's pretty good. We could make walking safer for pedestrians with better street design and limiting where/when cars and trucks can go. And no one is going to disagree that something has to be done with the MBTA before the infrastructure crumbles to dust.

I have had good luck emailing the public works department and asking such questions. Usually they just tell me when to leave the item out, assuming it is something that take, and they send someone (not the usual truck) to pick it up.