Gotta be Houston.
I figured Houston was going to be a top-tier team this year. Instead, they're last in their division, behind even New Orleans/OK City. I don't care why, but when you're averaging 90.6 points per game, with only Portland's 88.4 trailing you, that's bad.
Runner up goes to Golden State. This team should have been challenging for a playoff spot. Instead, they'll be the wost in THEIR division.