……….or a goal and they come back with “Let’s be realistic”, don’t listen to them.

Whether or not you actually achieve that said dream or goal is irrelevant – that you have a dream or goal is the point.
By sharing the dream or goal, you’re showing them that you have a vision of your future that isn’t stuck in the same place as this present moment, that you aspire to greater.

The doubters know this and feel intimidated by it, hence all the dismissive down-talk.

So when someone actually does tell you to be realistic, reply with joyous determination,

“Dream big or go home!”