Change admin password in Mac OS X, easiest way

What:

MacBook

Problem:

Forgotten or lost admin password

Solution:

Start computer in single user mode.
Reboot your Mac and hold down Command+S at boot to enter into the command line.

Recommended, but not necessary if system was gracefully shutdown:

fsck -fy

Mount file system:

mount -uw /

Check your username:

ls /Users

Reset password:

passwd username

Restart computer:

reboot