I haven't learned much Spanish from this app, beyond what I already knew from taking a couple of Spanish classes back in high school, but I sure learned what it was like to have a gaslighting stalker from the mascot bombarding my e-mail account with "reminders to study," and the green owl periodically getting sick or even dead in the thumbnail to ensure I feel extra guilty about skipping a day or two on the app.
No means NO, Mr. Duolingo Owl guy!