I have a strategy for my doctor as well...
1. Avoid.
2. If I can't avoid, then at least pretend there's nothing wrong.
3. If I have to admit I have a health issue then pretend it's a mild, uneventful, and isolated issue. And that my health situation is all rather silly and hilarious.
Perhaps it explains why I can't get any treatment!
Edit: Still, I've tried an assertive and persistent strategy too, and the ultimate results are very similar, so it seems to make little difference in the long run. In the short term, I get added frustration with an assertive approach, because the results are still negative, and I get gently ushered out of the surgery on occasion, or tearful.