These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Nightmare Retardant: When he does finally wake up, he resembles a giant space squid, and has an equally goofy voice.
Player Punch: The death sequence on any Tamagotchi is drawn out to be as heartbreaking as possible. This is turned Up to Eleven on the Gameboy edition, where you're forced to watch your Tamagotchi's last moments while sad, solemn music plays.
Scrappy Mechanic: The overall toy; many people have had less trouble taking care of a real animal than a Tamagotchi or anything similar.
Early on, the built-in clock. When the original toy launched in 1997, there was plenty of confusion as to what the clock was for. It was on the toy for two reasons: to give the Tamagotchi a practical value of being a watch, and to make sure the Tamagotchi woke and slept at regular hours. What happened instead was users put the clock to any time, causing the Tamagotchi to sleep during the day and wake up at night.
The Push Notifications for the iPhone edition quickly become this once the baby's born.
Everywhere in The Movie. First we have Mametchi breaking down to tears when he hears that the sun left Tamagotchi Planet because of him. Not much longer later, he falls into a black hole trying to save the planet, and he's TERRIFIED of the dark, followed by shots of the entire cast (including his little sister and family) watching on in horror. And we all knew that Tanpopo would go home at the end of the film, but we didn't expect Chamametchi bursting into tears, and the rest of the cast slowly following suit.
They Just Didn't Care: Bandai US's attempted revival, Tamatown Tama-Go, is this. With how little marketing Bandai did for the line, as well as how little product has been released, one must wonder if Bandai US even wanted to keep the franchise going.
They Wasted a Perfectly Good Plot: The iD L 15th Anniversary Version in Japan. It was meant to be a celebration of Tamagotchi toys for the past fifteen years...except Bandai put the character roster up as a poll on the site, where people could vote on which adult characters they wanted. As much of the original audience in Japan was gone and replaced with those who know Tamagotchi primarily from the anime adaption, the end result was only five vintage adult characters making the cut (out of 32 total adult characters), while the rest of the cast comprised of characters made popular by the anime.