Prime has the distinct feel of a favor. This wafer-thin romantic comedy offers nothing to distinguish itself except for the fact that Meryl Streep and Uma Thurman grace its cast. As the Jewish therapist to Thurman’s recently divorced New Yorker, Streep is more than willing to embrace her comic side, especially when her character discovers her 23-year-old son is dating her 37-year-old Gentile client. But writer-director Ben Younger botches Streep’s big “discovery” moment by jumbling it with a series of unnecessary camera cuts. When you’ve somehow convinced an actress of Streep’s caliber to be in your little movie, you might want to just stay focused on her face.