The tension isn't "Will they get together?" (we know they will). The tension is Watching Medaka’s monk-like composure crack by 0.5% every 20 chapters is more satisfying than a full confession.
Initially introduced as a somewhat vain and manipulative "queen bee," Mona quickly becomes one of the most endearing protagonists in modern manga. Her vanity is entirely transparent to the reader, showing up as an endearing, hyperactive work ethic. As the series progresses, her goal shifts seamlessly from "I must conquer this boy's pride" to "I am desperately, helplessly in love with him." Her dramatic facial expressions and internal panics form the emotional backbone of the series. Medaka Kuroiwa