When plants become your pets!
You know, I think I want to make something like that for books. It will go on the cover and display a sad face when you're not reading it. Also, it will be one more thing you'll need to change batteries in, as if you don't have enough of those already. Or, it will be rechargeable, which means another thing to recharge, as if you don't have enough of those already. Plus, in that latter case, it will probably be a lithium-ion battery which is one more thing that can explode and catch fire and, being that it's on a book cover which is a paper product, that fire is going to have some good fuel to get going. But, no need to worry because embedded inside the back cover of the book will be a stone slab with a sad face emoticon engraved on it. So, when the fire inspector goes through the scorched ashes of your home, he (or she) will crouch down over this stone slab, dust off the ashes from the book, spot the sad face emoticon and nod knowingly. So, even at the end, the book will display the appropriate emoji and that's, like totally, the most important thing EVAH in this day and age.