Countries that have enforced wearing masks, such as the Czech Republic, Slovakia, Japan, and Hong Kong, have had far fewer numbers of infected people per capita than in countries such as the United States and Great Britain, where mask wearing has not been strictly mandated.  Austria saw its number of cases drop by 90% within two weeks after making mask wearing compulsory.  Masks help prevent asymptomatic carriers of COVID-19 from spreading the virus to others.  This information can easily be found with a Google search.

I wear a mask because if the experts who compiled this data are correct, I could potentially prevent spreading the virus and causing someone else to become sick or die.  If the experts are wrong, then the worst that would happen is that I was uncomfortable for a little while because I wore a piece of fabric on my face.