The zemer "Shalom Aleichem" is obviously addressed to angels. The Tur (OC Siman 3) gives a short text to says before entering the bathroom: התכבדו מכובדים משרתי עליון, etc. (also obviously addressed ...
There are several things we don't do in order "to confuse the Satan", like not blowing Shofar on Erev Rosh Hashana. How does it help? Does Satan not realize that Rosh Hashana didn't pass yet? He ...