I spent a considerable amount of my young adulthood engaged in the pursuit of becoming a magician. My specialty was sleight of hand, as opposed to stage illusions or "box" magic. You might not know, but magicians spend significant hours practicing alone to perfect their sleights. While performing magic is a public endeavor, practicing magic is often a very solitary activity.
As a martial arts student attempting to learn a new defensive maneuver, there are three elements to master. First there are the techniques, be it blocks, strikes, kicks, or feigns. Secondly, there is the distance between you and the opponent. Newbies struggle a lot to get the positioning just right so that each technique can be effective. It takes a long time to learn the length of your arms and legs.
Lastly, one has to master the timing of each technique. You can't block a punch before it is thrown, and blocking too late is like having the perfect comeback an hour after you've been insulted. Of the three elements one must practice to master self defense, two of them require a partner. Handshakes, ballroom dancing, and martial arts - you just can't get better working alone.
That means you have a responsibility too, to be the best partner you can be. Let's say you are practicing a counter-attack against a kick. Your partner kicks and you are supposed to block, pivot, and punch back. Then it is your turn to kick and your partner's turn to respond. In this scenario, what do you want from your partner? You want someone who will force you to be good, and not let you reinforce techniques that are poorly executed, miss their mark, or are ill-timed.
When it is your turn to be the aggressor, you need to be a good partner. Is your role to be a kick, a punch, or maybe do a combination of moves? Know your role. Execute your technique with the same conviction and intent as you would defend it. Be focused. Care.
There are some situations where the partner's role is simply to maintain their position, to be a target that doesn't move. In Tang Soo Do this is true for our Long Distance Fighting techniques. Be a good target. Make sure your stance is correct, your hands are in a strong blocking position and your eyes are focused. By the way, even when standing in as a target, it's a good idea to stay engaged and alert - this is, after all, a karate class.
You want; no - you need your partner to push your abilities, to make you improve your techniques, your distance control, and your timing. It is only right, fair, and appropriate that you provide the same benefit when you are the partner. Be the best partner you can be.