Some applicants may ramble on about themselves in a manner that may appear self-indulgent and not very appealing to the committee.
Remember, this is an application essay, not an autobiography.
Don't write on general, impersonal topics-like the nuclear arms race or the importance of good management in business. Don't use the personal statement to excuse your shortcomings.
Social psychology is the scientific study of how people’s thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others (Allport 1998).
Again, mention the person and how their work relates to your interest, but don't load this statement with what might be interpreted as false or superfluous praise.
Some applications may ask you to give a personal history, telling about experiences that you have undergone which have led you to decide to pursue graduate education in a certain field of study.
The overall application package will represent who "you" are to people whom you will most likely not know personally.
The written expression of your qualities as an applicant will often be a very important way for committee members to get to know why you are an acceptable candidate for their program.
This is another one of those places where caution should be exercised: you want to explain the cause of your poor grades, etc. Do focus on an aspect of yourself that will show your best side.
You might have overcome some adversity, worked through a difficult project, or profited from a specific incident.