I like the gaming systems they have. But I really don't like the vaguely threatening notifications I receive if I don't do the lessons whenever Duolingo wants. Sometimes I have work and sometimes things come up and I don't need notification after notification telling me how "bad" I will be or how "bad" *I* will be if I miss a lunchtime session intending to make up for it that night. This is ridiculous. It is really very upsetting and it isn't fun.