It has to do with symbolic action, the basis of sympathetic magical practices. Taking actions on a small scale in mimicry of patterns and activities of a larger scale is a way of putting your mind into the moment, and creating a mental link between your will and what you want to use your will to change.
With candles as an example. Rubbing up from the base is comparable to the act of drawing things upward from the earth. Like a tree using its roots to take in water and nutrients to grow. Or like drawing water up from a well to drink. So when using candles to bring energy to you, it is made more potent by not just rubbing the candle, but also recognizing the large-scale act it is mimicking so you can consciously apply the action to the intent. Meanwhile, of course rubbing downwards is symbolic of casting things off or to the ground. Or even releasing energy into the ground and away.
Once this idea of symbols and their parallels clicks for you, you will see the applications everywhere in your magical workings. And you will feel a much deeper, and stronger, connection to the magical workings you are trying to perform. Because you won't be just doing some motions because someone said you should. But because you will connect those actions with their purpose and how they represent your intent and set it into motion.
Drawing a circle clockwise will not just mean protection. It will become the living symbol of the cycle of night and day. Cutting a thread won't just be an ambiguous cut of energy. It will become a severing of binding ties. Scrying into a mirror won't just be looking for visions. It will become reflecting on yourself and the world around you.