We've all heard the adage, "you can't judge a book by its cover." That's a great philosophy, metaphorically speaking, but when it comes to actual, literal books -- we do judge, to a great degree, the worthiness of what's inside by the cover design.
Rewarding though it surely is, writing your life stories takes a lot of time and effort. You want your stories to be read and enjoyed after all that work. So it's important to put some thought into what you want the cover of your book to look like. It should be immediately interesting and not too complicated, inviting the reader to open the cover and discover more.