If "practice makes perfect" then "there's always room for improvement" makes no sense. Why do we think up such contradictions?

We are meant to have minds that are sophisticated enough to take things in the spirit in which they're meant, not literally. "Practice makes perfect" doesn't necessarily mean one can reach perfection. It simply asserts the benefits of diligence. "Always room for improvement" cautions against pride.

Besides, human nature is not a computer that functions on logic. We're emotional beings and wisdom comes from emotional balance. Words of wisdom are meant to counterbalance each other.