Also that's why we have the trigger warning thing on posts. It's the red circle with an x in it. That's because for some people talking about things like self-harm, suicidal thoughts, etc. can trigger it in others or trigger memories which trigger things...
Trigger is a big vocabulary word for us.
Once you learn what they are you either have to learn how to manage them, like I have to answer phones and give directions. I can't just scream at people to stop asking me how to get to our office. I have to do deep breathing, remind myself this person has never been here before, etc. (I don't know why giving directions makes me seeth with rage, but it does.... )
Or you learn to avoid triggers. Like the no movies about cancer for me. Or songs that remind me of things.