[The tape] was used for all sorts of mending and attaching jobs, . . . and the notorious stubbornness with which it hid its end and tore diagonally off the roll were accepted by users as just the way the tape was. . . . But inventors and tinkerers like Drew saw each shortcoming as a challenge for improvement. . . . Difficulties in getting Scotch tape off the roll, for example, prompted the development of a dispenser with a built-in serrated edge to cut off a piece squarely and leave a neat edge handy for the next use. —The Evolution of Useful Things, Henry Petroski What drove improvements to Scotch® tape in the passage?