Why generics are better for me

I couldn’t understand what is generics for a long time unless realized that buying the original drugs Cialis, Levitra and Viagra in the drugshops – i just overpay for the brand. Of course i’m very grateful to these companies for development of such strong and effective drugs to treat erectile dysfunction, but i’m not going to sponsor the pharma magnates. I tried the generic variants of cialis, levitra and viagra (i prefer generic cialis) and realized that there is no any difference. So why should i pay more?