All nouns (common and proper) name persons, places, things, or ideas. There are differences between them, though.
Common noun: names GENERIC persons, places, things, or ideas (i.e. man, park, planet, religion)
Proper noun: names SPECIFIC persons, places, things or ideas (i.e. Billy, Central Park, Mars, Christianity)
Assuming you meant explanatory text and not exclamation text, the answer would be brackets. For example, say your quotation is "She wrote the book." If you are quoting this directly in a paper, you want your audience to know who "she" is. So, you use brackets, and write the following: "[J.K. Rowling] wrote the book." Hope this helps.
Answer: Because people don't want to possibly be made fun of or not have any friends for not following the social norm. Also people who are different tend to get made fun over more than "normal people"
Explanation: