Antipersonal Skills

I had the strangest thing happen to me at work last week. I was pulled aside by a middle-aged coworker to have a "quick chat", whereby she proceeded to point out that I have weak interpersonal skills and that she thought I had a tendency to make conversations with others somewhat awkward (as if I didn't already know that). Her criticisms revolved largely around three points:
1. That I mumble when I talk,
2. That I have an off-putting habit of correcting the grammar of others,
3. That I often don't pick up on cues in conversation very well, and in particular that I have trouble identifying when a conversation is over.

Now regardless of the fact that everything she was saying is 100% true, I was not at all prepared for somebody to actually approach me about this and was rather taken aback by the whole situation. And so when faced with the paradox of having a conversation about how awkward I make conversations, I did the only thing that came naturally: I made it awkward. After she had finished her shtick and was looking at me expectantly, I proceeded to mumble something about how I thought she wears too much makeup. And about how using breath mints every now and then never killed anybody. She gave a disappointed little sigh, looked at me as if to say "I am wasting my time with this sad fucker", thanked me for our little chat, and then waddled off to wherever she had come from.

WTF?