Minimising is a form of cognitive distortion - in essence, it’s not giving a fact as much acknowledgement as it deserves. Common example: I tell you that you make great contributions here, and you agree but have a whole stack of reasons why that doesn’t count for anything, and so you dismiss my statement.
I tend to find that there are 2 completely different ways that it impacts me.
Generally applied as a cognitive distortion to my everyday thoughts? Minimising tends to work to basically disregard my good points, or compliments I receive. I focus on the negative stuff, and when I’ve actually achieved something positive or done a good thing or been complimented, “it doesn’t really count because...”.
But minimising in terms of my trauma? It applies the same cognitive distortion, but tends to play out slightly differently. My trauma doesn’t count because... My trauma isn’t that traumatic because... My trauma isn’t such a big deal in my life because...
With the more general everyday thoughts, like if someone pays me a compliment? It’s more of the straght-up garden variety minimising - I can accept that the compliment has some truth to it, it’s just that I can totally swamp it with all my negative points.
When I’m minimising my trauma? I tend to be using the language of minimising, but what’s actually going on is closer to flat out denial - not being able to really acknowledge my trauma for what it is at all.