I recently heard the expression drill and kill. I hadn't heard it before and was told that it meant doing repetitive drills in a domain and thereby killing the interest in it. The instant I understood what it meant I was surprised. It is a mantra that runs counter to achievement. It's the repetitive cultivation of practical experience which begets skill; it's the skill possessed which begets true understanding; it's the true understanding which begets authentic appreciation. It is impossible to have a comprehensive appreciation of something without having known it intimately over time through experience and acquisition of skill. In other words, it's not the drilling which is killing, but the lack of drilling. Drilling doesn't kill interest; drilling is your only chance at reaching the best form of interested appreciation, passion.
Math is an often-cited subject with drill and kill. But math is like any other domain, it must be repetitively practiced to acquire rote foundational skills on which to build progress. With literacy we know we need to memorize the alphabet; then phonetics; then words; then master sentences, paragraphs, and texts. We know we improve at reading by doing it over and over. With math, however, because of preconceived urban myths of difficulty, we seem to fear the very building blocks of drilling which will render it workable. We don't learn our numbers well; we don't repetitively practice addition, subtraction, multiplication, and division for fluency. It's a shaky foundation not meant for further building; and it's little surprise that because many children are lacking in the basics, they then lose interest in the subject on the whole.
This is the danger with the drill and kill method. We assume the interest must be there first, not the other way around. And because we assume this, we don't really commit to the drills. And because we don't commit to the drills, the subject seems harder than it is. And because the subject seems harder than it is, the commitment to learning the subject wanes. And because the commitment wanes, the interest in valuing the subject dies. It is a dangerous presumption to assume that interest needs to precede commitment. With math, it can change the child's outlook on life. He or she might decide a whole realm of careers are off-limits because he or she is "not good at math." But really, the truth was that math was never really drilled as it should have been, to develop the confidence to go the distance in the subject.
There seems to be more common sense about drilling with sports. We somehow more easily understand that it might take intensely repetitive skill-building effort to free solo El Capitan or win Wimbeldon. Perhaps because the acquisition of skill in a sport transforms the player in a concretely visible way, in a physical way which can be seen and appreciated by the masses, we understand the link between years-long practice and success. But no matter the endeavor, it is actually only by drilling that we get to a level of expertise, and it is only in the acquisition of such expertise that we begin to cultivate appreciation.

In sum, there were numerous things I didn't understand as a child before I embarked on them, about which I am incredibly passionate today. I would never have known the value of these entities before embarking upon them; it was only by doing over and over, and making mistakes, and repairing my mistakes, and growing, and continuing to practice that I began to acquire the experience from which I developed my skill. You come to love and appreciate something if you're good at it and you can only become good at it if you practice for years. The practice at first may not be fun but if you apply yourself over time there will be a payoff. It is absolutely dangerous to assume any child is fully capable of knowing before starting, or shortly after starting what the depth of a domain entails. If you want your child to be proficient, they will have to commit to learning with repetition and memorization in order to use these basics to reason and build further. It really isn't drill and kill; it's: drill and instill skill.