A lot of people use words and numbers in passwords that are familiar to them. This is a problem because it actually makes the password easier to crack. Hackers use 'word-lists' which contain dictionaries of words and use hacking software to find your password.
Even reversing the letters in a password does not help! A secure password needs to contain a combination of lowercase and uppercase letters, numbers and special characters on the keyboard.
The length of the password matters as well. It is important to have a long passwords (minimum 10 in length).