Answer:
I'll give you a specific example of what is true for me, but everyone’s experience is different and the things that trigger them are different. Hopefully you can find something useful in my story.

One day my therapist brought it to my attention that whenever I felt I was being ignored or “blown off,” I had a severe emotional reaction that was not equal to the situation. At times, the smallest slight in which I felt ignored, would cause me to drown in a sea of self-depredation often ending in suicidal ideation. It was an incredibly intense overreaction to things like someone being late to pick me up or in the middle of a conversation the other person’s attention becomes distracted by something else.

The first thing I did when I realized the truth of my behavior was to look into my past to see the source of this reaction. I realized that my sensitivity probably happened because I was raised in an invalidating environment where I was a stepchild (not of “REAL” blood), a scapegoat, and after the age of 13, I spent nearly half of every year alone at home because my parents were working out of town. Even more convincing was the years I spent with my father who insisted that I should frequently be reminded, "nothing you do means anything, nothing you say means anything, you are nothing."

Connecting my reaction to this past experience was helpful. It made it easier to forgive myself for having the response. I'll admit that when I understood the reason for my reaction, I was tempted to get stuck and feel really sorry for myself. My therapist helped steer me clear of this by validating my hurt feelings from the past and encouraging me to take the time to grieve over it. She also reminded me that it's now the present and the beauty of this realization is that there is an opportunity to recover. I could now begin
to choose another course of action.

Next, she pointed out that my inappropriate response to being ignored wasn't JUST about the past. It was also about having Borderline Personality Disorder and BPD people tend to be reactionary and make instant judgments and assume they know the reason for the actions of others. Here again, this helped me to forgive myself because I had been convinced that my response was just "stupid" and "crazy" and
that I was "bad."

After that, I thought back about the times in which these triggering situations occurred when I felt ignored and tried to get an "emotional memory" -- an understanding of what it felt like in my gut when the reaction happened.

I tried to catch myself having the reaction, which was difficult because I rarely realized what was happening when it happened. Over time and using skills, I got better at recognizing it sooner and sooner.

I started to break it down. My therapist and I would discuss a recent situation. Then, she’d encourage me to remember the exact feeling I had when I felt “blown off.”

The feeling was a kind of angry distance. When I was ignored I would separate myself from the person and get an attitude like, "I hate the world and the world hates me and my existence sucks and THAT'S JUST THE WAY IT IS." It was like a hard-shell feeling; like “I'm tough and I can handle anything and no one else understands me. I'm an island.” The  more familiar I became with the feeling, I could see a hurt little girl inside me, angry and pouting and horribly betrayed. In my imagination, she would just stomp her leg and cross her arms and turn away into the corner and say, "na, na I'm not listening to anyone because everyone is so mean!"

When I looked at it, I thought, "Wow, that's a pretty heavy and distinctive emotional response." Maybe I could try to notice when that response is happening and turn on a little light and say, "Oops, this is a trigger and I'm tempted to stay like this, but I think I'll look for an alternate instead."

In the old days, when I didn't do anything -- I just let the response spiral downward, it would always turn into self-hatred because that was the response I had become accustomed to.

I still don't always recognize the response the instant it happens, but I'm getting closer to it. So I put 2 and 2 together. "I'm having that icky feeling AND someone did something that I COULD interpret as blowing me off."

DBT jumps to the rescue and I consider my little arsenal of skills - and depending on my mood, I begin choosing what's helpful at the moment. Opposite to Emotion Action is a good one. I feel like hating myself, but say affirmations instead. Distraction is usually really good. I decide to put off thinking about the upsetting situation for the moment and schedule a time to think about it later (maybe with my therapist). In the meantime, I'll read, or take a bath, whatever. Building Positive Experiences might be good by working on a project where I have a sense of mastery.

This is what has worked for me. My therapist used to always tell me, “Do whatever works right here and right now, whatever it takes in order to keep yourself safe.

Lisa