Hopes and dreams are part of planning our future, part of discovery, and part of creativity. We begin as children answering questions like "What do you want for Christmas?" or "What do you want to be when you grow up?" We hope that our dreams come true.
Dreams may just be wishful thinking, but we need to have some idea of the probability of them happening. We also need to realize what it may take to make them come true. Even if we do our part, some dreams will not come true because of happenings beyond our control or because they no longer serve our purposes in life. At that point, better to imagine a revised version of our future.
Revising our dreams requires us be logical. Putting all our eggs in one basket can be very risky. Hoping for some magical solution to ease our loneliness, calm our fears, and solve our problems can also be risky. Better to look toward a reachable star, than to hold on to an impossible dream.