Season two of HBO’s “Euphoria,” which aired its finale on Sunday night, has made headlines for many of the same reasons as its first: in short, anything but the show itself. Through its nine-episode sophomore season, “Euphoria” has functioned more as a collection of moments, ebbing and flowing in and out of one another with no real sense of direction. The approach was as thrilling as it was tedious, offering an experience that could, at once, be genuinely unpredictable and frustratingly aimless.