Most people believe that choosing a good password is easy.
In reality, people usually choose poor passwords. One fifth of all password were obtained in the first week and approximately one quarter were cracked by the end of the search. More than half of the cracked passwords were six characters or less and some accounts didn't even have a password. Choosing a good password is a trade off between something that is difficult to guess versus something that is easy to remember. Conversely, your first name is very easy to remember, but it is also trivial to guess.