Isn't the stock market "weird"?
Each time someone sells a stock, someone is on the other side buying. But they both think they will be right! Otherwise they wouldn't have bought or sold respectively right?
OK, that's half in jest. What I'm trying to say is, when you invest or sell, be humble and aware of the fact that you could be making a mistake.
It's OK to be confident (in fact necessary) in your decision making process because otherwise you should not have done it. Do enough research to build conviction in your decision. At the same time, never allow hubris to overcome your judgement.
Be confident whilst being humble. "weird" eh?That's investing!