I was taught to rinse rice before cooking until the water runs almost clear. This can prove a ritual with many in the East. The rattle and slosh of rice being rinsed over and over is a lullaby to many children. There is no need. Rinse as you would your teacup and sing them a lullaby instead.
The theory goes that rinsing before cooking rice removes excess surface starch and so produces a whiter, cleaner-tasting dish. With long-grain rice this makes the final product more separate and less sticky. With sticky rice grains, it reduces โ ever so slightly โ the stick. Win win.