There's a ton of talk these days about boundaries. Mostly about family members having "bad" or "no" boundaries with each other. These issues come up when one party decides to try and manipulate another party into doing something they don't want to do. Or when one party behaves in a way that annoys another party. But boundaries are a little more complex than just being annoyed (or, actually, identifying whose boundaries are the non-existent ones in that case). For instance, if someone is getting on your nerves that person doesn't necessarily have the boundary issue: You do.
Boundaries is the shorthand way that we discuss individuation in our culture. Having clear, solid boundaries is code for being a responsible, emotionally stable, reliable person, nowadays. Not having clear, solid boundaries is synonymous with being an emotional mess, a drama queen (or king), manipulative and generally unattractive.
So, what are boundaries?
When someone "sets" boundaries with another person, it means that they are indicating to that person (verbally or not) what types of behavior are and are not acceptable to them. So, as an example, Joe and Kerry have just met and Joe puts his hand on Kerry's shoulder. To set a boundary, Kerry politely says, "Please remove your hand." If Joe doesn't not do so, Kerry may remove his hand for him and emphasize her boundary by explaining that she does not like being touched by strangers. (Although the explanation is not necessary.) Kerry, in this case, has strong boundaries and is sticking to them. She is polite, yet firm, because she recognizes that different people have different expectations as relates to acceptable behavior and so she doesn't take offense to Joe's initial ignorance. When he ignores her first request, though, she takes appropriate action to secure her own sense of stability (individuation) and to re-iterate her boundary (no touching) and reason, with the understanding that Joe may need an explanation to justify her boundary.
That's a pretty simple example since it's physical. It gets complex is when we're dealing with the emotional.
Emotional and psychological boundaries are much more difficult to maintain and to respect, since they are not tangible. The easiest example I can offer of lacking in emotional/psychological boundaries is the following. Have you ever been in a situation with a parent, a sibling, a partner and after you did something provocative they said the following: "Now you ruined my day!" or "I was having a great time until you did that." or "You make me so angry."
This is a very typical version of having a lack of boundaries. The spouse, parent, partner is reacting to you as if you have some magic power over them to "ruin" their day or change their mood. The reality is that they are allowingyou to "ruin" their day or change their mood. And, most likely, they are allowing you to do it because they have no boundaries with you. They are not individuated from you. They see you as an extension of themselves and if you are unhappy or acting out, they must, too, have similar feelings.
It's the developed, individuated person who can see their spouse, child or partner act out or misbehave and not have a personalized response. These people respond more like, "I see that you're very upset and I'm not going to engage you like this." And they go about their business. In a world where people do not have excessively merged psychologies with others, it is possible for one partner to be in a great mood and maintain that great mood while attending to their partner's very cross mood.
This is to say that the crux of having boundaries is realizing that we are individuals with very little to do with one another. Most of the time when someone acts out, (whether it's getting stupidly drunk, picking a fight, not showing up on time, lying, having a tantrum) it has almost exclusively to do with that person.
Parents who become irritated or angry with their children who won't listen to them are not angry at their children. No. They are angry at themselves for not doing a better job teaching their children to listen to them and follow their instructions. Yet how many children have been taught that they are "bad" and "misbehaving" and that they have made their parent angry? What a destructive and backwards lesson to teach a child. First, that the way they've been taught to behave is wrong (who taught them to "misbehave" to begin with, eh? The parent!). And second that they have the POWER to change the mood, the state of being, of their omniscient parent. And then the child grows up believing that he has some crazy power to bring out the worst in people, so he becomes an enabler and walks on egg shells around all of his loved ones.
If you're walking on egg shells, you do not have strong boundaries. And, probably, neither does the person you're walking on eggs shells around.
So, when someone acts out, it has to do with them. Not you. And you are not required to be upset by someone else (no matter how close you are to them) being upset. It is not rude to be steady and stable in your own emotional state while someone else is in theirs. And if someone tells you that you just "ruined" their day, know that this person needs stronger boundaries. (I mean, unless you purposely hit them with your car or something.)