NBC has decided that, well, maybe Friends isn't the "best comedy ever" after all. The network promised Thursday not to rerun a much-criticized promo in which it used that phrase to refer to the departing hitcom. An NBC spokeswoman concedes that the spot "went overboard." She'll get no argument from Frasier star Kelsey Grammer, who last week expressed his dismay at the ad. "I don't blame them for saying that," he said. "Although, we all know it's not true."