Keeping your fingers crossed - superstition or a courtesy phrase expressed in the words I keep my fingers crossed !. As superstition, it refers to forces that are most likely unable to change events. A person declaring holding thumbs has then no other option to influence the development of cases other than belief in supernatural power. In turn, as a courtesy formula, keeping your fingers crossed occurs during interpersonal communication instead of wishing good luck, then expresses the desire to keep happiness for another person. The superstition of keeping your thumbs comes from ancient times. For the warrior, the thumb was important because without him he was unable to hold the weapon. Holding your thumbs was therefore a protective gesture. The customfirst spread among the Germans.