Capturing the moment is much easier for one's brain to send down the right signal. Besides, the ball didn't even know that you were on the verge of panic. Another key issue is how to practice intelligently. Blocked practice is when the person practices the same stroke and shot over and over again, either against a practice hitter or ball machine. Variable practice is when the person hits one particular stroke, but varies the shot.
Random practice is when the hitter practices all of the strokes in a random fashion.
The motor learning people put it this way. A player, to be successful, must have a motor program for a high forehand that his opponent hit to him. Then, he suddenly has to rush up for a short backhand. Then the dirty rat on the other side throws up a lob. Before you get mad at me, I'm not suggesting you give up ball machines.