In the pandemic I became astonished seeing how a lot of doctors were quick prescribing the likes of chloroquine, and other ineffective treatments, even after they were proven bogus. Really shaked my trust in the profession. Today I'm afraid of taking medical advice before I have the opinion of at least two and they agree.
Another presumption, that people who hold these jobs are necessarily smart. I used to be fooled into believing it. I think many people are fooled.