When half the students say "It was just obvious stuff" it means that it was an incredibly useful and essential class for the other half.

I remember talking with two students who took a class my friend was teaching at uni: it was critical thinking with several example of typical manipulation techniques, from marketing techniques to what cults use.

One student told me "It was interesting but a bit obvious. Anyone knows that, no?" and the other one said "I learned a lot of interesting things about source checking."