Yeah sometimes people say "doctor I have X, I'm trying to get diagnosed with X". You're biasing the doctor to give you a diagnosis so you don't drop them, and you're biasing the doctor to ignore your symptoms because you're just saying them to get the diagnosis and maybe you just want to get certain medication.

Even if you don't outright say it, you should never convince yourself you have a diagnosis. The human body is extremely complex and some particularly weird issues need patient research, doctor's research, and experimentation to solve.

What you say is often true. But never say never.

I recently had an appointment with specialist for my son. My son has ADHD but was never diagnosed within Kaiser and so Kaiser won't prescribe medication.

The appointment started with, "My son has ADHD, was first diagnosed at 7 by _____, here are volumes of paperwork demonstrating that he had this diagnosis, has continued to have symptoms, and documenting what we have done for him. He wants to go back on medicine despite the side effects from last time. Here is more documentation that he continues to have symptoms."

There really ARE times when you're coming with enough background that the diagnosis is never in doubt.

For a less recent but more trivial example, I once showed up to the doctor and said, "I broke this bone in my hand while playing volleyball, what should I do about it?" Again, the diagnosis was never in doubt.

If you manage to hit the exact diagnostic questions they were trained for, that's the same, actually worse, than saying you have X, because you'll make them think they had the idea that you have X, when in reality you saw the list of symptoms, thought "I guess I have those," and then repeated them to the poor unsuspecting doctor.