If I've learned one thing on this site, it's just how much denial and dysfunction there is in this world, and how many people are unable to cut through the denial and make good decisions for themselves.
I used to doubt my own judgment, but I thought that other people were generally together and competent. If someone believed strongly and loudly about something -- an opinion about me, about a relationship, or even about life -- my default presumption was that they were probably right and I was probably wrong.
I no longer doubt my own judgment the way I used to. After a couple of years on this site I am far more discerning now about what I believe of the stories and opinions of others. This goes for everyone in my life -- family, business associates, spiritual advisers -- everyone has their issues. No one is perfect. Nor do they need to be.