The challenge someone faces who struggles with PTSD is how much more "sensitive" they are. So, it's more challenging to engage and interact like a person did before they developed PTSD, and a trigger can literally develop into the individual experiencing a rush of chemicals in their brain mainly cortisol that presents the person with feeling they are in danger, and will need to act on that danger, fight/flight/freeze. I know if I have to face some very toxic or challenging things myself, I find that I NEED to find a dark quiet place that I can feel safe in just so I can actually "rest" and feel safe where I don't face any kind of outside stimulation that might trigger me. No one means to have this challenge either and one thing that is so hard about it is how others in our lives don't understand how challenging it is and also how exhausting it can be too. How a trigger can literally leave a person genuinely feeling like they ran a marathon and are just exhausted.