When someone tells you that you will FAIL if you do what you want to do how d'ya react? Believe them and don't or do and prove them wrong?

I have ignored naysayers my entire life and succeeded a few times doing things "they" told me I should not do because I would fail. I didn't. Not once. So do you let folks dictate what you do with your life and change your direction or do you just go about living it and ignoring them...not the yaysayers who encourage you to do but ignoring the naysayers who don't know what the he** they're talking about?