Probability "Zero"

I found out why they claim certain things Probability "Zero" (or "One" in some cases). When talking about infinite possible results, the probability of a finite number of results is "Zero" since the the probability goes to zero as the number of possibilities increases to infinity. Even though the probability is "Zero" doesn't mean it can't happen.

For instance: I sold my Numerical Analysis textbook since I had Probability "Zero" of ever needing it again. However, over the infinite amount of time (assuming time is like the Real Line) there are a finite number of moments where I could use it, like finding a way to do least-squares regression for Bézier curves over a set of points.