Instagram doesn't care if you see all your friends' posts in chronological order. But it does want you interacting with the month-old photos its algorithm picks to appear above and below more recent posts. The latest example is a change to how commenting on posts works. Instead of responses all getting grouped together, replying to a comment will automatically create a thread. Handy! It's a minor tweak, sure, but one that somehow wasn't present until now. Maybe an opt-in button for the algorithm-driven timeline will be next. Wait, why are you laughing?