Off topic, but I really think I need to tell a joke. Unfortunately it takes a little explanation. In the traditional English translation of the Bible, a verse reads "Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them." The phrase "to cast pearls before swine" has entered the language as a stock phrase, meaning don't share things with people who can't appreciate them.
This underlines, by the way, that we think of "swine" as "the kind of word you know from Shakespeare or the Bible."
In the traditional US (patriarchal, male chauvinist, pre-feminist, socially conservative) cultural tradition, it is polite to open a door for someone, or hold a door open, as a sign of respect. Thus, the order with which people go through a door is a mark of social hierarchy. Thus, traditionally men hold open doors for women (occasionally saying "Ladies first!" Or, as we used to say in elementary school, "Ladies first, they're the worst!"), and people hold doors for older people. Of course, and again according to patriarchal-etc. tradition--women want to appear young.
The story goes that Clare Booth Luce and Dorothy Parker (never mind who they were) were vicious rivals who liked to insult each other. Clare Booth Luce held the door open for Dorothy Parker, saying sweetly "Age before beauty." This is also a stock phrase, but of course here it was an insult because Luce was saying that she was young and beautiful and Parker was old and ugly.
Parker immediately retorted, "Pearls before swine."