For the most part, pool follows logic and, despite the sometimes daunting body of knowledge that we must accumulate, most of it falls into place predictably as we build on a set of good fundamentals and basic cue-ball skills. Usually, it's not that complicated. When we need to move forward to the next shot we use follow, and, when the next shot is behind the object ball, we choose a draw shot for position. Sometimes however that logic does not apply, and very subtle differences in a shot's setup can demand an unexpected variety of choices to get position for the next ball.
In the diagram we have three different shots on the 8 ball into the upper-left corner, represented by three cue balls; A, B, and C, each separated from its neighbor by one ball width. Although the setups for the three shots are similar, each discrete angle may demand its own position choice to get on the 9 ball for a shot into the bottom-left corner.
Cue ball A, the dotted-outlined cue ball on the far right, offers an almost straight-in shot on the 8 ball. To be precise, in this case you would cut the 8 ball very slightly to the left with draw, which, of course moves the cue ball slightly off to the right and back toward the 9 ball, as shown with the dotted line. The 8 ball is exactly one ball width away from the cushion and two diamond segments up table. The cue ball is two ball widths away from the cushion. This precise setup offers the draw option we see in the diagram. You should set up the shot and adjust the cue ball's position slightly to examine other possibilities. For example, the most difficult shot in this vicinity is the one where the cue ball lies a little farther to the right to present a shot on the 8 ball that demands a slight cut to the right. When the angle is just so, draw moves the cue ball backwards along the side rail; trying to follow two rails can scratch or catch the pocket point coming out of the corner; and a straight bounce off of the side rail with stun draw can require Herculean speed.
When the cue ball moves over one ball width left to the solid-outlined ball at position B, the best position option begins to change. From this spot a draw shot may still be viable, but be careful. As cut angle enters the picture, drawing straight back becomes more challenging and requires and short and snappy stroke, a soft touch and a very short follow through. Any extra speed or stroke length can send the cue ball swinging out to right and across the table. It does not take much cut angle to make drawing the cue ball into position too difficult if not impossible. A better option in this case would be to play the cue ball with a straight follow, a high-center hit and a smooth stroke, to carry it forward to the top rail and then back down toward the 9 ball, as shown with the solid line.
Moving over one more ball width to the left and cue ball C, shown with a dotted outline, presents a new position challenge. From this position, draw becomes very difficult, with a wide swing out to the right almost a guarantee. Some players might let the cue ball go wide right to the opposite side rail with draw and some right-hand english to bounce down toward the 9 ball. That's an important shot to know and a good one to practice, perhaps at first from an easier position with the cue ball away from the cushion. Straight follow to track along the solid line may look like a good option again. But, from this position, that requires some inside english (left), which makes the shot more difficult and position somewhat unpredictable. Since the shot angle introduces a natural swing to the right for the cue ball, it's best not to oppose that movement. So, from this position, the most natural position choice is to let the cue ball go to the right with follow and a little right-hand english to track two rails toward the 9 ball on the dashed line path. Keep your tip high and your stroke smooth to prevent the cue ball from swinging out too far to the right for a possible two-rail scratch in the left side pocket.
As I watch beginners and intermediate players I observe this month's theme popping up repeatedly to cause problems. When we see two balls that relate to each other as the 8 and 9 do in the diagram, choosing draw to move the cue ball back toward the next shot appears logical and correct. As we see however, it does not take much cut angle to introduce too much lateral cue-ball travel and a lot of difficulty. Set up the shots in the diagram and practice them until you can identify angles where going forward is the best way to move the cue ball backwards