"This Is the WORST DAY EVER!"
This exclamation was made by a highly sensitive child (HSC), when, after a wonderful day with hours of fun and joy, her dad said "no" to going back downstairs (once she was already in bed with lights out). She insisted she needed to check on a Magnatile structure she had been working on earlier that day.
I can't tell you how many times a week I hear stories like this from parents. Their HSC has a great day with lots of good stuff; and then one, often seemingly minor, event/disappointment happens and everything is ruined.
After decades of working with families of HSCs, and parenting my own, I understand that this is often part of the deal with these deeply feeling kids: they live life at the extremes. They are ecstatic or enraged. They tend to process their experiences in this all or nothing, black and white way. It's all good or all bad. They have a harder time living in the gray.
The temptation, naturally, is to try to get them to see that there was so much good in their day, to talk them out of this all-encompassing, negative state, which seems so unfortunate and sad—for them to see the world this way. But that usually results in the HSC, in reaction to being told how to feel, doubling-down to prove to you that in fact, everything is indeed ruined.
Keep in mind that this doesn't mean the good stuff isn't getting through or having a positive impact on them. This awareness may also help you avoid the temptation to try to get them to acknowledge it or feel it in that moment.