Most of us are beset by a legion of passwords. The suckers keep changing and so that complicates matters.
Even if you use a site that compiles them in one secure spot, it's wise to make a regular habit of updating them.
Wander down Memory Lane and see the multitude of your password changes. That can be a great reminder of why relying on your memory is not a sound strategy.
And yes, it may be wise to use memorable phrases from songs and literature to confound the villains.