You're open and suddenly your not. You have the ball and suddenly they've knocked it out of your hands. You're on your man and suddenly he blows past you and is dunking it.
They are fast, sure, but their reactions and hands are elite, maybe world-class.
It's hard to fight sudden because each action is over almost before you know it.
Plus they're very disciplined. A lot of fast team you can use their speed against them. Houston doesn't over-pursue and somehow plays FAST and under control.