While it may be tempting for teachers and students alike to get right to the nitty-gritty of executing patterns at tempo, often the real treasures -- or truffles! -- of practice are found by attempting to complete patterns accurately at an almost painfully slow tempo. When we have students attempt a pattern at a tempo that seems ponderous or plodding, little errors in timing and stick control quickly become exaggerated and evident.
That's important because groove doesn't lie, no matter the tempo. If we can't execute a pattern slowly, but we think we can at tempo, then there's a good amount of hand-waving and guesswork involved there -- and most likely it doesn't sound as good as we may be convinced that it does. We want to be secure in our knowledge that we're playing precisely the notes that we intend; no more, no less!