One problem is that when people are triggered by certain topics, they will still be triggered by the topic, no matter how careful or non-violently you approach. If you are married, and your trigger topic is house work, it doesn't matter if your spouse says "you need to more house work" or "when I get home after a long day of work, I feel let down by having to do a large amount of house work, could please do more in t…
The observation wasn't there. I initially wrote "I think we can both agree that it is not needed in this context.", but on reflection that's a really poor assumption. Because (and trust me, this is common), the other spouse may actually have tidied the house (or done laundry or whatever), and is now dealing with the complainant complaining as if he/she hasn't done any work. It would help a lot more if the complainant specified the problem.
Did you mean to say "I feel down" or "I feel let down"? The latter strictly violates NVC (it's not a feeling but a judgmental narrative). It will trigger defensiveness.
The spouse didn't state the need. Having to do a large amount of house work is not a need.
Your example is one of the most common types of problems between two people. One side is OK with a sloppy house, and the other isn't. The way you phrased it, the other spouse is likely to respond with "So don't do the house work. What's the problem? I'm fine with it, why aren't you?"
One spouse perhaps needs more order than the other. Unless that is made clear, how will progress be made? Is this obvious? No. Because it may not be about tidyness but about a filthy bathroom where the need may be sanitation. I'm not being splitting hairs. I know people who insist on very clean bathrooms and kitchens, but are not at all fussy about stuff all over the floor in the house.
Finally, the request was a poor one. Both the observation and the request need to be specific, not general.
Imagine that the other spouse had put effort in cleaning up, and is being requested "Could you please do more in the future?" More what? What will it take for you to be happy? And did I just waste my time doing something that you perhaps don't care about? Should I waste my time telling you what I already did?
Defenses are up.
If the other spouse managed not to be triggered and knows NVC, his/her response may be "Are you dejected/annoyed because you need the house to be more orderly?"
A better NVC statement from the original complainant would be:
"I came home and there were several of your dirty plates on the countertop, and the sink was empty. I have a need for tidyness. Would you be willing to place your dirty dishes in the sink if the sink is not full?"
To your wider point, though, of course - if there is a history of conflict on a particular topic, anything can trigger them. Looking at several comments here about technical debt and managers, I think I see it in action. :-)