A leader does this:
After having a dream, leaders expose it to reality, adjust the dream in light of that reality check, turn it into a vision (a reality-checked dream with an implementation plan), then set about turning that vision into reality.
Dreamers who aren’t leaders do this:
They have a dream, then because they are more concerned with maintaining their dream than turning it into reality, they bubble-wrap it, protecting their dream from harsh reality lest it not survive. After all, who wants their dream to be crushed?
All of this is fine so long as the dreamer is deluding no-one but themselves, protecting no-one’s dream but their own. The danger occurs when the dreamer masquerades as a leader (or deludes themselves that they are one), and starts leading others up to the top of the hill – and down again – to no purpose, with no effect, no execution.
Are you a leader with a dream? Or just a dreamer?