Another exploration of this theme was in an episode of Doctor Who (Smile) which features a colony with nanobots that are optimized for happiness, with disastrous results: https://en.wikipedia.org/wiki/Smile_(Doctor_Who)
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"The Vardy were programmed to help construct and operate the colony and make the colonists happy, monitoring the emotional state of the colonists through the emotion badges and avatars. When one of the flight crew died of natural causes, it created grief among the crew, something the avatars were not programmed to register. The Vardy took this as a sign of disease and killed those who displayed unhappiness. This created a "grief tsunami" which rapidly wiped out the flight crew, and will likely wipe out the waking colonists when they discover what happened."
If you enjoyed reading this, you may also appreciate the novel Ella Minnow Pea by Mark Dunn. As letters are banned in the story, they also are omitted in subsequent chapters.
If you find yourself running out of battery power, an extra powerpack can come in handy. I ordered one earlier from newtrent.com this year and use it a lot more than I thought I would. Lots more other manufacturers too if you do a quick search.