Take knocking on wood, thought to date back to pagan rituals aimed at eliciting help from powerful tree gods. We still do it today, though few, if any, of us worship tree gods.

Knocking on wood in some places it's called "touching wood," but knocking on wood for luck is an almost universal compulsion.

Every time he came back after business trip with knocking the wood door after opened the iron door by himself, and I always could hear the voice although I closed the bedroom door.