There is nothing quite like being an introvert when the extravert you're trying to avoid speaking with says she "learns a lot" about people by the way they respond to conversational topics they may not want to discuss. Do you:

1. attempt to explain the difference between introversion and extraversion?
2. assert that you, too, learn a lot about people who force others to converse with them?
3. tell her that, ah, you understand: she's only offering her ridiculous opinions to see how others react?
4. explain that this might account for why no one likes her?
5. give it up as a bad job and turn with panting relief to the person joining you?

Alas, she might learn a great deal more about me if she could see this thought process, but in the meantime, and in the spirit of polite discourse---at least on my end---I suppose option e is the best.