The Yea-sayer Nay-sayer is a so-called school-opera written by Bertolt Brecht, Elisabeth Hauptmann and Kurt Weill in 1930. Initially it was titled The Yea-sayer, and the plot revolved around the question of whether an individual must be agreeable to sacrificing themselves for the good of society.
In the first version of the piece a boy gives permission for his own execution. After a sting of discussions with students and workers Brecht’s The yea-sayer was modified into a second version, where the yea-sayer is presented in contrast to a nay-sayer.
This nay-sayer calls the blind obedience of the yea-sayer into question. The function of the yea-sayer has seen a variety of literary interpretations; perhaps the most common interpretation being that the character represents the expression of a false obedience with regard to authority and social norms.
Indeed, the term yea-sayer has a negative connotation in the German culture. To be a yea-sayer means to say amen to everything. Not to resist. To accept anything. Better to be a nay-sayer in this case.
Nay-sayers may be more complicated and unpleasant for those around them, but at least they stand up for their own beliefs. An (initial) no could simply be a way of expressing oneself first.