What must David Mamet think of The Decameron, Netflix’s laughless comedy of medieval prurience and plague? In the 1990s, long before his turn as a conservative provocateur, the dramatist was famous in iconoclastic circles for his condemnation of modern acting, with its endless “funny voices.” Yet strained artificiality is the new production’s primary mode, not least in the performance of Mamet fille, Zosia, formerly co-star of HBO’s Girls. An exceptionally loose adaptation of Boccaccio’s 14th-century masterpiece, the show is a veritable feast of screeches, squeals, gasps, and unlikely accents. If the high priest of “just say the line” directing has a kind word for his daughter’s recent project, I can’t imagine what it is.