The fact is dreams are dreams. Dream may happen or may not happen.

I dreamed of floating in the air walking and running.
Will it happen to me?
I don't know. I don't know if that was my soul, maybe it will happen.

When we dream big and wanted to achieve that big dream and failed in the end, we end up frustrated, depressed and eventually we get sick and die a sad death.

What if on the other hand we dream small, then take things slowly. In the end, we're satisfied of what we have, leading a simple and good life without regrets because our small dream is achieved. Then we get old happy and satisfied of what we have and die with acceptance.

When we were kids, many people surrounding us would ask, "What do want when you grow?"
As kids we see our parents as our model and the people around us are the first attraction in our lives. And we as kids want to be like them when we grow.
But as we grow, many other things and people will influence us much more.
And we start to think, "What am I for?"