The meltdown triggers of the moment are so all-encompassing, I found I would never notice all the things that *weren't* a problem any more. So I often stop and wrack my brain trying to take notice of all the triggers that slowly fell off the list without me consciously realizing they are now gone. This process brings me a lot of relief on days when I want to scream "you're X years old and I'm STILL dealing with with WHAT?!!"
But - - - I don't have to think about which cup I give which kid. or bring dishes when we travel. or worry about having the wrong book or clothes on an overnight, because they pack their own. or worry about using public toilets, or, or, whatever all those things were that used to make me feel just as you describe. As teenage existential angst replaces toddler-style breakdowns (well, most days, anyways), my lists are different, but I'm still making them, and they still really help me get through the bad days. It's always getting better in a bunch of ways, honest! It's just hard to notice, some days.