Falling in and out of love.
There are reasons why we abandon some of our hobbies. Sometimes we don't have enough time to engage in it anymore, prioritizing different things; sometimes we find stuff that brings us more joy and replaces the previous source of serotonin; sometimes we decide that we just grew out of what we enjoyed; sometimes the spark is just gone. With anime all of these things are possible, but you can't alter memories: you can't carve out of your mind the moments when you were sitting on the edge of your seat watching an epic battle filled with suspense, or when you cried watching a heartfelt confession at 3 AM, or when you laughed your heart out at some silly but entertaining filler.
These memories sit dormant in your head until you, after not engaging with anime for years, stumble upon something that piques your interest and nudges at this passion that's been inside, asking you to try it once again. Some people on Twitter shared what shows served for them as this spark that got them back into watching anime, and their preferences are interesting in their diversity.
One GIF can be something that would trigger your Pavlovian instinct and make you do some research. In one person's case, it was a GIF of Angel's Egg that forced them to look it up, watch it, think that it's weird, and keep thinking about it for weeks, helping them find that curiosity they thought they lost.
To some seasoned anime watchers, those who have been engaging with this medium on and off since the 70s, Your Lie In April showed them that "there was something beyond fighting and cutesy characters". A few people listed Jujutsu Kaisen as something that brought them back — both the first and the second seasons. There's something in this show that makes the general battle shounen tropes work in a different way, despite having an overpowered boy as its main character. The lore itself, built from urban legends and folklore with an added twist, creates a solid base for the character development (although some fans disagree with the direction the manga has taken for the past few years).
Other works cited as helping people reignite their passion for the anime were Magi, Steins;Gate, Princess Kaguya, Attack on Titans, Nana, Madoka Magica, Mononoke. Others said that re-watching the previously beloved series also worked, reminding them of what they felt back then and why they loved the medium.
People sometimes abandon their hobbies, and it's fine. But anime is an ever-changing industry, and sometimes it's worth trying to dive back into it. Maybe you'll find another gem that will stay in your memories for years.