No one here has yet really considered the real elephant in the room:

Why does anyone need an "intelligent" thermostat, especially something as overhyped and over-engineered as Nest is?

I never even remotely bought into the Nest hype from the very beginning. Ditto on their smoke detectors.

At least, you stop being such a baby and turn the heat up or down by yourself. Controversial, I know.

At most, you put your thermostat on an automatic schedule, which can be done about a thousand different ways (timer circuit, dippy bird, microcontrollers that have already been manufactured and tested in a million different ways by more established companies).