The Lottery- Pagano

I am not religious, so there are few ritualistic acts that I partake in. Although everybody does some sort of ritualistic act every day. For example, every time I comment on something good and I don't want the opposite to happen, I knock on wood. But why do I do this? I guess my answer to that would be 'why not?'. If people believe that because I said "wow what a beautiful day", it is going to rain, and the only thing to prevent this from happening is to knock on wood, then why not give it a try? What harm could it do to knock on wood? When I was trying to think of a way to explain what it is that would make me knock on wood, it took me a long time to figure out what to say. It made me wonder why it is exactly that I feel the need to knock on wood. "Why not?" is the only answer I can come up with. Or maybe just because my parents do it, and I've been doing it for most of my life.