The goal of each workout is to set a record.
I do not really agree with this rule. They are not saying that you need to set a personal record every time you workout, but that you should never do the exact same workout twice in a row. You should always strive to lift heavier weights with the same number of reps, or more reps at the same weight, or the same reps at the same weight if you did something else in the workout that left you tired. The authors want you to improve in something every workout.
Most weeks, especially with my lifting, this is the case for me. But sometimes, you just need to gut out with the same as what you did the week before. When I am running, I will often go out for easy 4 or 5 miler, sometimes more than one day in a row if I am still beat. I do not feel that I should run faster every time I go out there; that would be counterproductive as it would leave me tired and other workouts or races would suffer as a result.
I also believe that every once in a while you should intentionally cut back on your workouts. My general plan is to increase my workload from week to week for 3 or 4 weeks, and then to take a week where I cut back on my mileage or on my weight before resuming an increase in the 4th or 5th week. This gives my muscles a little extra recovery time and can lead me to even greater gains than just trying to get better all the time.