There are plenty of reasons to believe the Boston Celtics' 13-game winning streak will end on the TD Garden floor Thursday night when they host the defending NBA champion Golden State Warriors. There may be teams that have better players, but you would be hard-pressed to find any group in the NBA that can claim to be a better team right now than the Celtics. Frankly, the closest team to them along those lines is the Warriors (11-3), who are also off to an impressive start.