WALTHAM, Mass. -- The Boston Celtics and Washington Wizards have developed into one of the?NBA's most unexpected rivalries in recent seasons after a series of flare-ups between the teams. As the teams prepare to meet in the Eastern Conference semifinals, Celtics players downplayed the notion of bad blood on the eve of Game 1 but acknowledged the possibilities for tempers to flare again. "I think it's just two teams playing hard, and there's a lot of guys on their end that play hard, play nasty, play feisty, and I think we have some guys like that," said Celtics forward? Jae Crowder, who's been a featured player in many of the Wizards incidents over the past two seasons. "Two teams like that come together, you have little situations and encounters, but I think it's just two teams playing hard." Crowder admitted that he likes that the two teams seem to elevate their play when they go against each other. "If you don't stand up to it, those guys will...