I think the '09 Celtics were 28-2 by Christmas...then they lost an intense Finals atmosphere X-Mas game to the Lakers, and followed it up the next night with an unexpected flat footed 4th qtr L to the Warriors (BDiddy, Cap Jax), in which they were prob a bit emotional drained. After that, they kinda came back to earth plus had to deal with injuries (KG).
So as good as the Warriors are looking now, season is too much of a marathon with letdowns and injuries to make much about 7 games. We've seen teams go on big winning streaks (leading to 70 win hype) only to take that first L and become a bit deflated with some concurrent Ls afterwards.