I like this very much! I have copy/pasted your paragraph with some suggestions.
Don Quixote frequently allows for his imagination to flow freely, constructing a belief that his actions are producing “good results.” Despite Don Quixote thinking that he may be doing something beneficial, his deeds may be causing more harm than good, which is counter-intuitive. (leave this part out)
What is depicted in Don Quixote also occurs in the ordinary world, books, and movies. For instance, a lot of the time (replace with "many times"),
people contemplate whether or not,(delete comma)to tell the truth or let the mystery consume them with questions.(I don't know what you mean by this)
Truth-telling is a hard concept to decipher between doing good or causing more harm (Do you mean: Telling the truth can be difficult. Sometimes it can result in doing more harm than good.).
Oftentimes I see shows that it is better to not tell the truth as it can be detrimental or too heavy of a burden to carry, but the counterargument would be that is unknown more harmful than the truth? (This sentence was the most problematic I think that you are trying to clarify the previous sentence, but I am not sure. I think you are saying " I have seen shows where telling the truth was very difficult, emotionally. However, sometimes telling the truth can be more harmful than not speaking at all." Like I said, I am only guessing at your thoughts.
I hope this helps!