The true quality of pasta can be tested by cooking smooth pasta shapes!
Grooved shapes were in fact a solution discovered by die makers in the 1950s. The grooves prevented the pasta pieces from sticking together during the drying process.
True craftsmanship in the art of pasta making can be seen in the production of smooth shapes that do not stick together, that remain separate from each other when served and are not coated in a sticky film after cooking. Good quality pasta binds well with sauce because of its porosity, not because of the grooves or the starchy film (known as stickiness) coating the surface.