Why do we throw confetti at a wedding?
Way back in the day at English weddings, as a Bride and Groom exited the church it was custom for the guests to throw rice over the couple. Rice was a symbol of fertility but it also hurt when it was thrown at you.
In France it was more common to have flower petals thrown which obviously hurt a lot less and looks much nicer. This had evolved to small discs of coloured paper. The wealthy English aristocracy and society folks loved to keep up with new trends so they took this trend of coloured paper back to England and these pieces of paper have evolved over the years to become the modern manufactured confetti we know today.
Thankfully with environmental concerns in modern times, the tradition of flower petals is coming back!