What is a ‘tiny trauma’ of yours?

I’m currently reading the book Tiny Traumas by Dr Meg Arroll and it got me curious. There are major traumatic events like war, getting attacked, getting bullied, abusive childhood etc. And then there are microagressions, toxic positivity, a sentence that just triggered a vulnerable spot.

To paraphrase the book,

“Think of an event or experience which impacted or changed you in an important way, but you thought it wasn’t serious enough to mention?”