As mentioned, this part of your application can be used to decide whether a school wants to invite you for an interview or not. Schools only accept students who have been invited for interviews, so getting to this step is a huge part of the process.
Focusing on negativity _ People face problems from time to time; however, there are those who have faced graver trials than others. If you are one of those people who's had your fair share of problems, make sure that you adopt a positive attitude despite the challenges, and reflect this attitude in your statement. Wallowing in negativity will give off an unfavorable vibe, and enumerating all the trials you've been through will no longer make your essay an interesting read.