I had no idea how to respond intelligently to this, and still can't.

It varies from one person to another, one day to another, one situation to another. I'm trying to learn to take it as it comes and goes, and not try to have any iron-clad rules beyond "Protect myself without hurting others."

You said "without causing problems". Well, IMHO, if the boundaries are not respected when you're established them, that IS a problem....

The key here being, let others know your boundaries. I am learning to say simply, "I have PTSD and can't handle XYZ right now." Most people do get a little bug-eyed, but my real friends and true fam (that'd be my real friends, my mom, and the whole two other relatives I still bother contacting) get that it's not something I am making up and am not playing as some game. And my ability to cope varies from day to day, too, so.... I kinda keep a running commentary to those who need to know (therapist, hubby, mom who lives with me, etc.).

I'll add a twist to what Deli said. How much is you, how much is them, and how much is the possibly bad pre-set patterns between you and them? Back in AlAnon, we had to ask that when trying to bust our co-dependency issues, and it's been useful to remember now.

Gentle healing wishes,
Leo

I would just be blunt , firm and nice at the same time. Say your piece. Set the boundary,
If your still getting pushed, after that........ Speak your piece again.
Rinse and repeat as needed.
Some people may not get it. But they do not own your thoughts.You have every right to set boundaries, I.E. saying what you will and will not put up with or deal with.

Yeah, wellbe. My dysfunctional family never got it. I had to separate from them for my peace of mind and I got it. The letter I wrote them when I separated from them was nice, not mean. Not for their sake, but for my sake so I wouldn't feel guilty and go back on my own word.

The fact that they didn't get it wasn't because of any flaw in my communication. My therapist read my separation letter and assured me it was nice and crystal clear. The fact that they didn't hear it is because they're so nutty they're deaf to what I say. They're so used to having anything from me any time they want it that they don't understand "no" from me. That's why I got molested and beaten and mentally and spiritually violated in their home.

It's them, not you.

Muji, Mine didn't get it either , hence I have nothing to do with them, and they me.
But I can say I did try my very best.
Sometimes , well often in my life it has caused an immense amount of pain to keep true to my boundaries once I finally hit the brick wall and discovered fully what they were all along. What I knew was there deep down but hoped for something my abusers could not provide.
I thought my communication was flawed for so long.
Its what they wanted me to think, to hush me up or contort the facts.
Now it bleeds over to adult life.
Such a balancing act.