You're probably right, but saying that stubbornness can be good is my tactic for dealing with people who think I'm stubborn. It moves the conversation from what they think of me personally to whether I'm right or wrong.
In regards to what other people accuse you of, it's usually them projecting. In other words, the person who accused you of being an egomaniac could be avoiding fears that they themselves are being an egomaniac. Or the person who calls you a liar may secretly be afraid that they're not trustworthy.
Regardless, I've found experience to be the best teacher. I've learned not to be shy when it comes time to say "I told you so". It sucks, but you leave people the option to continue to underestimate you if you don't.
I think people called me egomaniacal in part because I am a woman. I strongly suspect I would be considered more humble if I were male. They call me a liar because they find my claims threatening. If I am right, then their doctor is wrong and that has ugly, uncomfortable implications when your life (or your child's life) is on the line.
In regards to what other people accuse you of, it's usually them projecting. In other words, the person who accused you of being an egomaniac could be avoiding fears that they themselves are being an egomaniac. Or the person who calls you a liar may secretly be afraid that they're not trustworthy.
Regardless, I've found experience to be the best teacher. I've learned not to be shy when it comes time to say "I told you so". It sucks, but you leave people the option to continue to underestimate you if you don't.