Writing with a Purpose (Brief Example)

As a I read some other papers, I wish to remind you again of having a PURPOSE in everyhing you do in writing.  For example, I just read a description of a person that seems to have no purpose:  he was fat or tall or short or had blonde hair.  Description should have some kind of purpose, if only to make us SEE the person speaking a line.  For example, writing, "He was short and chubby," is not very purposeful.  But if you write, "I saw his short, chubby fingers grab my slice of pizza before I could put it in my mouth," here description and purpose go together.