Comprehension Dismissal
Asserting that the other person "missed the point" or "didn't get it" without ever saying what the point actually was.
"You completely missed the point."
"I think you may have missed the point of the book."
"You're misunderstanding the argument. Badly."
"If you don't get it, I can't help you."
Why It's Unproductive
Announcing that someone missed the point, with no account of what the point was, ends the exchange while adding nothing to it, and it leaves the other person unable to respond except by guessing. It's tempting because it claims the higher ground for free and recasts any disagreement as a failure of understanding rather than a real difference. But a point that's never restated can't be engaged with, so the conversation just stops.
The Better Move
If someone genuinely misread the point, say what the point was. The correction only helps if it includes the thing they supposedly missed, stated plainly enough that they could now respond to it.
Why It's Better
Restating the actual point gives the other person something to engage, and it lets bystanders judge for themselves. It also guards against the awkward case where the "misunderstanding" was really just disagreement.
Examples
OP: "I liked the sequel, but the ending felt like it undercut the whole first book's message."
Antipattern: "You clearly missed the point of the first book."
Better: "I read the first one as being about accepting loss, so the sequel walking that back bugged me too. What did you think it was going for?"
OP: "So the takeaway is that the new format is faster but uses more memory?"
Antipattern: "You're completely misunderstanding what they're saying."
Better: "Not quite. Their claim is it's faster only for streaming reads. For random access it's actually slower, which is the part that surprised me."
OP: "I don't see how this analogy about traffic applies to network congestion."
Antipattern: "You just don't get it."
Better: "The link is that both have a tipping point where adding more load drops total throughput. That's the piece the analogy is leaning on."