Too hard to remember for us that might have gray moments. so I prefer abreviating phrases with characters, upper and lower cases and so on.........
It really does come down to whatever really works for you. Each person has their own methods. The phrases seem to be the most popular.

I worked with an elderly sys admin deity who had memorized entire verses of poetry and would create personal passwords from them in the same manner in which you do with phrases. It just seemed somewhat phenominal that someone could actually remember a 20+ character password including special characters...

So, once again, it comes down to whatever it is that works for you. Just be sure to follow the best practices set forth in the industry. And remember, even if you give your users obscure passwords, they will memorize them after a week or two of having to type them in 5+ times a day. That's just how a brain works. Truly amazing