How you interpret your so-called reality determines how you react to it. And those reactions are what actually matter.
Whenever I post about the impact of beliefs on lives and careers, I tend to get at least one comment contrasting "optimism" and "realism." That's an odd comparison to make, because they're actually the exact same thing.
Let me explain.
Because you are human, you are not capable of discerning "reality." Everything you see, hear, feel, smell, and taste is being channeled through your mind, which assigns meaning to all of those events.
So your experience of reality is actually an experience of your interpretation of reality.
Now, the world around you consists of a long list of things that you can't control and a short list of things that you can control. That short list, in fact, consists of exactly one item: the actions that you take.
Defining Your Future
Those actions emerge from your interpretation of reality--that is, the meaning you assign to events and their importance to you. To the extent that those actions are creating your future, your interpretation of reality is therefore also creating your future.
If your interpretation of reality is basically pessimistic, you'll make decisions out of fear, be far less likely to take risks, and you'll miss opportunities that might change your life for the better. Plus, on a daily basis you'll be experiencing fear and dread, both of which impoverish your life.
By contrast, if your interpretation of reality is basically optimistic, you will tend to take more risks, try new things, and be alive to the wonderful things that might happen. More important, on a daily basis you'll be experiencing excitement and anticipation, both of which enrich your life.
Why "Realism" Isn't Real
In other words, there is no "real" in "realism," because your interpretation of reality creates your reality. Therefore, optimism is the same as realism.
The exact same thing, however, is true of pessimism.
So the only real question is: Which realism are you creating for yourself? Is your realism a state of enjoying life and looking for success? Or is your realism a state of misery that's carrying you toward failure?