Quotes:
"Two roads diverged in a yellow wood..." - Robert Frost
"You must be the change you wish to see in the world." - Gandhi
"Nothing will work unless you do." - Maya Angelou
Ect. ect. ect.
There are a lot of inspirational quotes that you can put in your personal statement, however, none of them say anything unique about you. The Admissions Committee wants to know how you will be a good fit at their school, not about your ability to find obscure William Blake quotes from your Poetry 201 class. Quoting another person only says something unique about the quoted and takes the focus off the substance of your essay. Spare the Committee their time and leave the quotes for your Facebook status updates.
Resume Regurgitation:
A resume is an outline of your experiences and successes. A personal statement is a persuasive essay which shows your ability to add a diverse viewpoint to the classroom and strengthen the learning environment. The two are not the same. The Admissions Committee is looking for something much deeper than a superficial regurgitation of your history. They want something that shows your passion, motivation, and drive. Something that only you can add to the learning experience to not only propel you on the path to success but also challenge your classmates to broaden their horizons. A long-form outline of your life story does nothing to help the Committee make a decision on your application.
The Superhero:
Everyone has a superhero - someone who inspired them to be the person they are today. It is wonderful that they helped you get as far as you have gone, however, at some point you have to do it for yourself. The personal statement is where you need to pick up the torch and leave the accomplishments of others behind and talk about your own accomplishes and challenges. As inspiring as the story of your (grand)parents immigrating to a new land/ building a business/ raising 18 children/ fighting a war may be, that story does not tell the Admissions Committee anything about you. It only tells them that they should accept your superhero.
The Sob Story:
This sounds cold but everyone has bad things happen to them. Admissions Committees read about unfortunate circumstances all the time and it can get downright depressing. Committees are not looking for unfortunate sad-sacks to feel bad for; committees are looking for the inspiration that changes a bad situation into an opportunity for growth. Everyone likes a comeback story (otherwise Hollywood wouldn't make any money). If you write about a difficult situation focus on the turn around and how it transformed you into the wonderful person you are today - not just the circumstances which you had to overcome. Admissions Comittees are looking for someone who overcomes challenges, not someone who wallows in them.
The Plagiarized Personal Statement:
Do not, I repeat, do not plagiarize your personal statement. You will get caught and brought before the LSAC Misconduct and Irregularities Subcommittee and your application to every law school will have a black spot on it for the rest of your life. If (by the grace of a very forgiving Admissions Committee) you do get into law school with a plagiarized essay, you will still have to explain it to your Board of Bar Examiners to get your license to practice law. It may sound dramatic but it cannot be overstated. If your personal statement sounds like any of the example personal statements on a blog or from a book you should throw yours away and start over again. There is too much to risk when a committee member can just plug a sentence from your statement into Google and find the example essay you pulled it from. Law school and the legal practice is heavily ethics based and having a plagiarized personal statement is the wrong way to get started in your new career.