Iv had a smartphone and tablet for about 4 years and through that time, apps have come and gone, eventually, you'll stop playing them, here's a list of some that I got stuck on for a while.
Dragonvale - theme park builder, it was whimsical and addictive and I eventually tired of the constant stream of limited edition dragons to breed
Hay Day - it was better than FarmVille, but eventually suffered from repetition. As you advance the cost of machines becomes too expensive and it gets hard to keep up with demands without spending cash
Subway Surfers - like Temple Run, but it makes less sense, it's addictive but you run into a lot of plateaus in advancement.
Candy Crush - this one got its hooks in but eventually I ran out of levels and I'm still waiting for more.
Clash of Clans - a town/base builder with elements of tower defense/attack, it can be played casually but you only make real advancement by spending cash... lots of cash.
Draw Something - I liked this, it was fun but it got a little old putting time and effort into drawing a convincing picture only to have your friends just write the word, if you can't play properly, don't play.
None of these lasted for more than 6 months though, Candy Crush is pushing it, if it had more levels, I'd still be playing. What's 1 game iv had for the entire 4 years and still play every day? It's the very first app I downloaded, the first one I paid for, I still enjoy playing it and it's also a great way to keep up with your friends.
Words With Friends - it's nowhere near as good as Scrabble, but it was the first mobile version of the crossword game that allowed multiplayer. Scrabble only added the feature last year... way too late, WWF has already got a stranglehold on the service, Mattel allowed them to muscle in on their turf and then let them take the market. The best mobile game iv played then is Words With Friends for sheer longevity.