Resetting lost password
If you've ever forgotten your user account's password in OS X, it is still possible to reset or change your lost password. All you need is to remember your username and then reboot your computer. From there it's command line work
You should know your username in order to perform the password reset as outlined below. The username is usually your computer name.
Hold Apple+S when booting to enter single user mode, then enter the commands below.
Note that the process above will reset all your keychain if you ever have to use it. Anyway, this is better than no password at all -