Of course they are silly. Of COURSE I have some. My biggest one is that I will not walk under a ladder, not way, no how. Never did and hopefully, never will.
I do cross my fingers for luck, hate it when a mirror breaks (oh no, seven years of bad luck,) but I don't take these things as seriously as the ladder. On the other hand, I don't hate the dreaded number 13 or even Friday the 13th. I do notice when a black cat crosses my path but I can deal with that, no problem.