Notions/beliefs only hold as much sway over you as you allow them to, by the proportion that you believe them to be correct. While there are some universal truths which match reality no matter what, a lot of the beliefs we hold are subjective. Sometimes there are multiple outcomes, and you can choose which one you want to take and practice taking that option instead.

For example, if someone insults you... you do not have to take offence. It does not have to hurt you, it does not have to reflect or define you. You can choose to reject that insult, to dismiss it. Then it holds no power over you. Once you learn who and what you are, the impact lessens because you know yourself. It doesn't apply. It only applies if you believe it does.

Not that it is nice when people insult you. But you can choose whether to consider what they say as an insult, or even just listening to them.

The tricky part really comes when you get defensive because what they said is the truth. Not just something you believe in or not. Then you have to reconcile that with yourself. Lashing out at them for pointing it out won't work. If you find what they say is correct, then it is a call to action... whether to acknowledge it, and whether to work on it if it is something that involves improvements on it.