There’s no better way to keep your running interesting than to have peaks and valleys of intensity and duration woven throughout your training weeks. Multipace training naturally builds a structure into your running that makes it more enjoyable.
When you regularly do all sorts of workouts, from long runs and basic speed sessions to slow recovery runs and tempo workouts, the variety keeps the days from all blending together. The days have meaning not only in regard to themselves, but to what precedes and follows them. If you’ve done a long run on Sunday, then you’ll probably go slow and short on Monday. That sets you up for a hard workout Tuesday, followed by a recovery day Wednesday. By Thursday maybe a medium-effort run followed by some short, fast quasi-sprints to rev you up for a tempo run on Friday will be the ticket. Then you could finish the week off with an easy day on Saturday to ensure you’re good to go long again on Sunday.
To continue our cooking analogy, most people who like to cook find doing so more interesting the more they switch things up, from complex creations to simple stir-fries, from quick scrambles to dishes that take hours to make. In running as in most things in life, not having every day seem like the previous one is motivating.