It sucks how Duolingo has gotten so much worse over the years. It used to be great when it had the grammar notes and discussion forums and comments, and you could actually finish the course and have some recognition. Now it's just all too game-like and all based around maintaining streaks rather than learning. Unfortunately some other apps have started to copy this model too like HelloChinese.
It was really nice to discuss the sentences with other learners and the creator of the course.
And it was always fun to open the thread for the sentence "I love you" in the language that you were learning.