Before Al-Anon, I had an attitude common to many people - that my personal rules of etiquette were the "correct" ones. So if you did things differently, I'd respond in various judgemental ways, but the end result was that you were wrong, I was right, and why wouldn't you change to fit yourself to my rules?
We all have various things we consider "rude." It's rude to read at the dinner table. It's rude to eat in the livingroom. It's rude to say "I don't feel much like talking right now, but I'm happy to listen." It's rude to wear shorts to church, not to remove your hat indoors, to walk in front of me, to cut in front of me when driving, to 'steal' my parking spot, to fold towels differently than the way I showed you way back when we first got together...
The list is endless, and varies wildly from one person to another. If a friend, partner, or family member does something which contravenes our personal rules of etiquette, we have several ways in which we can respond. We can say, "I wish you wouldn't wear your hat inside the house," and then engage in a power struggle, trying to force them to remove it; they'll most likely be equally as determined to keep it on. We can harp and yarp along those lines each time they enter the house and don't remove their hat, and by doing so, create a major issue between us.
We can look at this "rule" and ask ourselves, "Where did this originate? Is this a rule I learned in childhood, or did I make this one up by myself? What is this about? Why do I care? How Important Is It?"
We can decide that we are going to let it go, stop taking it personally, stop allowing ourselves to extrapolate from that hat, all sorts of stories inside our own heads about what that means with regard to their respect for us and our living space, wishes, wants, blah blah blah.
When I decide to make a big deal out of the fact that another person's rules of etiquette differ widely from my own, I am creating a problem where none exists. Now, understand I'm not speaking here about someone stomping all over personal boundaries set to keep myself safe and comfortable - I'm talking about the wider range of etiquette rules such as "Towels must be folded in thirds lengthwise, then in half." "Cups go into the cupboard with the bottoms up." "Never put into the sink, anything which can be fitted into the dishwasher." "Never put anything into the dishwasher without rinsing it first." "This is how you fold a fitted sheet. It's rude not to make conversation first thing in the morning. People should sit at the kitchen table to drink their first coffee, not at the computer, or the tv. You should never interrupt when someone else is speaking."
Some of us, (and I include myself in this group) have a tendency to rigidity in our personalities. If not carefully paid attention to, this character defect can cause problems for us, by insisting that everyting be done "our way." Why? Well, because that's the right way, of course.
When I learned that I could let go of all of this, and nothing major would happen, the house didn't disintegrate into a slum, the dishes still got clean regardless of how they were loaded into the dishwasher, (and if they didn't, that didn't matter either, they could be rewashed) that I was "taking offense" where none was ever intended, and I was doing it around these rules of etiquette, that was enormously freeing.
I'll share something which I suddenly realised about 10 years into practising this wonderful program of ours: I've never yet worked to let go of something, only to wish I had it back. Never. Those rules and regulations of mine kept me a prisoner in my frustration. When I let it go, and it's gone, and I can look at whatever is happening with no need to take offense or get all worked up, I feel delighted.