The language that we everyday use to communicate with has no definitions behind it. More complex words can be defined using simpler words. But the fundamental words that we use everyday have no definitions for them. Even if we were to introduce a definition for them we would then have to define our newly defined words. This leads to an infinite regression. Language is never defined. Instead we learn words by experience. The words "black" and "happy" were never defined to us when we were kids, rather we learned by experience to what experience/perception do these words apply to. Thus, when we think of "black" and "happy" we do not think of some more fundamental definition which can explain those words but rather an experience associated with those words. What is language then? Language is the communication of our experiences between ourselves. We never communicate with rigorously defined concepts between ourselves but rather experiences that we have; we understand each other by empathy.
One word that we communicate by empathy and learned by experience but causes much confusion is "truth". Many people try to define what truth means. But they run into the same infinite regression problem. So if we cannot define exactly what we mean by truth then how can we know exactly what we mean by it? Experience of what "truth" meant is what we know exactly what we mean by "truth". When we learned the word "truth" we realized that what is true is part of the world (or "reality" if one wishes to say). Thus, when we say that a certain natural law of physics is "true" we mean to say that it is part of reality, that this is what the world around us follows. Now some people might object to me and say that I am not defining truth and that I may sound as if I am circular, but that is all irrelevant. Because all we care about is the experience that is associated with the word truth. What is important is to know what this experience is in order to understand how we learned what truth means. (There are additional problems with what I said. Truth can have different contexts. For example, in mathematics truth follows from the mathematical system that we have, but it need not be true in the way described above. But again this is all irrelevant because what I care about is the experience associated with truth). Therefore, the word "truth", what it means to us, is having correspondence to reality.
With that introduction now I want to get to exactly the point I wanted to make. One of the most abused expressions that I hear is, "I am realistic and you are not", or similarly, "you are being unrealistic". Truth is correspondence to reality, anyone who says, "I am realistic" can equivalently make the statement "I am truthful". When one says, "you are being unrealistic" it is equivalent to saying "you are wrong". When one says, "I am a realist but you are not" is equivalent to saying "I am right and you are wrong". I refer to this as one of the most abused expressions because this phrase, "I am realistic" or "you are being unrealistic", is often used within an argument. In certain cases it is used as an entire substitute for an argument.
If I present my own point of view and I can develop it but my opponent responds to me saying "you are unrealistic", then what he basically did is responded to my position by saying "you are wrong". If someone makes an argument and you respond "you are wrong", that is not a refutation. Such a response is not worthy or any respect whatsoever. It is a response that anyone can make. This is exactly why I have no respect for the argument "you are unrealistic", it is a non-response just like saying "you are wrong". One who says "I am a realist" should deserve no respect just like a person who says "I speak truth", that is an absurd self-statement for a person to make.
In fact, it often turns out that people who claim that "I am a realist" turn out being wrong on so many issues. What the realists claim is that they derive truth by observation. But if the observation is incorrect or if the explanation given to the observation is incorrect then the realist will most likely be wrong himself. The phenomenon I describe is extremely common with the self-identified realists who tell me that humans are evil murderous rapists. I wrote my position concerning human nature here, even if I am wrong, I think it is quite obvious by thinking it through that people cannot be demons. If that was the case our species would have been so inefficient that it would have died out a long time ago, we survived mainly because of cooperation. But the self-identified realists usually tell me how evil people are. They see wars and murders so they jump to the conclusion that people are so evil. These realists have the correct observations but they explain their observations in a terrible manner, for instance they never consider to compare the evil people to the good people on a grand scale level. The truth also sometimes turns out being counter-intuitive, which will lead the self-identified realists to error. The planet being round, evolution, or the invisible hand, sound so ridiculous at first, and so counter-intuitive that the self-identified realists will never derive these statements, unless it was explained to them why these ideas are true. This brings up another problem that I have with the self-identified realists. They almost always seem to think that the truth must pessimistic. But why? Sometimes the truth can be positive. I agree that in most instances pessimism is the correct way to proceed, I am a nihilist myself after all (which can be considered as the extreme form of pessimism), so I have no problem with denying our meaning in life, but there are a few occasions where the truth is positive. These self-identified realists love to preach pessimism and mask it under the name of being "realistic".
My entire point of all of this is that people who call themselves "realistic" or people who tell you "you are unrealistic" or people who say "we need to be realistic" are making a non-argument. It is redundant to say in a discussion "we need to be realistic" because that is equivalent to saying "we need to find the truth", obviously that is redundant and has no point of being mentioned in a discussion. All what being realistic means is simply saying "I am right and you are wrong", a response to which no respect should be given at all.