The reality is, numbers are used for accounting. If we start keeping an accounting of small actions such as that, what freedom will we have?
People being mean, nice, depressed, etc. they are what make is human. By accounting for the little things we’d incentivize uniform behavior and lose all diversity of any kind.
I too think on those little things a lot. I recently had a family member move away, and since then every family get together is just flat in comparison. I think in a small way, those flowers did the same to the neighborhood.
Sometimes I think it’s enough to say, we lost something when they left. Or gained something when they were here. Maybe that’s enough of a quantified “number”.