When I was kid, my mom and I would often walk on either side of a pole and then say “bread and butter” when we came back together on the other side. Today, while we were driving, she brought it up, asking “I wonder where that comes from?” Immediately, I decided to find out.
Turns out this “bread and butter” tradition dates back to at least the 1920s, if not earlier. It is a superstition that if a couple (either romantic or friends) is broken apart during their walk by either another person or another object, they must say “bread and butter” when they meet up again, or they are doomed to have a conflict later on. The thought is that bread and butter go together, and that bread, once buttered, cannot be “unbuttered.”
Although my family has only ever used “bread and butter” in this way, people have also used “salt and pepper” in this superstition.
Source: Signs and Superstitions Collected from American College Girls, published by American Folklore Society in 1923
Read for it for free online: http://wwwjstor.org/stable/535105