Do you know about the above? It's slang for TOO LONG; DIDN'T READ.
TL;DR when you want to chime in about a topic, on an email thread, that you don't want to read.
This is a rude reaction, I suppose, but there's rudeness when a recipient receives an email that clearly, you are cc'd on for the straightforward reason that the sender wants to give responsibility to you. They volley it to you and it's almost as if you can feel them wiping their hands and sighing, "There! Done with that!"
I've surrendered. I'm done managing my inbox. I just periodically move everything to "Inbox Old" and carry on, artificially blissful at my quiet inbox.
Managing my time may still be a personal challenge, but dang it, I can manage my energy.