It is a good thing to dream. Dreaming helps keep the creative juices flowing. It gives energy. It can help one rise above present circumstances, which can be helpful if things are difficult. It can bring balance and perspective. Dreaming is invigorating and can bring about new things. And I hate it when feel that I don't have the capacity to dream anymore.
But in reality, do I ever really stop dreaming? I think not.
There are times that circumstances and life and obligations and pressures and reality staring you in the face make it almost impossible to even conceive of dreaming at all. Surviving the next moment is all that matters. All the energy is sucked right out of you.
So at those points dreaming must put on a different face. It is forced to happen at a different scale. There is no margin. No space for big dreams at all. In those times, it all may be reduced to dreaming of simply putting the next foot forward, or making it through the day.
I have experienced those times. And the other times.