How to make the app addictive

Any app on a mobile phone has to compete with social media apps. So the developers had to implement features to make learning addictive:

• streaks
• friend streaks
• quests
• friend quests
• reward chests
• notifications
• passive aggressive notifications, if you've been slacking too long
• competing in leagues: your first week, you're in bronze league in a group of 30. At the end of the week, the first 20 with the most XP go to silver league. In silver league, the first 15 get promoted and the last 5 get demoted. Then you progress to gold league, sapphire league, ...
• achievements