THE BLUE ROOM, Katharsis Theatre Company, at the Athenaeum Theatre. Just in case you didn’t realize that sex can leave people feeling embarrassed, frustrated, elated, angry, disappointed, guilty, bored, or saddened, David Hare is prepared to enlighten you. When his loose adaptation of Arthur Schnitzler’s century-old classic La Ronde opened on Broadway in 1998, critics must have been deceived by Nicole Kidman’s naked body into thinking this was important theater. But in the cold light of morning, it’s difficult to find much depth in Hare’s leisurely orchestration of “ten intimate acts” between talkative, only marginally interesting heterosexuals. Whether it’s a taxi driver and an au pair in a storage closet, a middle-aged politician and a teenage model in a hotel suite, or a Broadway diva and her rich fan in a dressing room, these encounters seem unremarkable, having little impact on the participants and less on the theatergoer.