The urge to collect all the items, achievements or secrets in a game.
"You can get awards and rewards for completing tasks in bonus games, and upon completion of a "bingo room". I never thought this was a problem, but I've now been playing four years, and have yet to finish a final achievement on at least two of the rooms. It seems impossible."
"They added "Legendary Bitizens" a couple of years ago, and I'm still far from completing those collections, even playing for hours daily (unless I spend money), and now they're hinting that they'll be adding more soon. A lot of people, including me, find them irritating (they're in the way in your tower), but many are still spending big money to complete their collections. There are also seven extra towers you can build to earn extra points and such, and I'm sure there will be more of those."
"There's like 15 playablee character, each needs 10 stars to unlock, which means 10 levels, and there's only one level a day. You cannot buy stars and there's no gameplay benefits to the characters, though. Just skins."