Slightly related: I have a bad tendency to slip up names between people who have similar personality traits or from whom I'm looking for similar behaviors.
With an almost embarassing amount of regularity, I call my boss by my husband's name and my husband by my boss' name. Not because I get them confused, but because they both have many traits in common (this is a good thing). I usually make the slip when I'm asking one of them to do something for me which I might ask the other one to do.
I blame it on early onset senile dementia
