Remembering a password is no harder than remembering a phone number
It must be so difficult, living in modern times. Apart from having to remember your address - or getting lost 'cos you've forgotten where you live. Or your registration number and wandering the neighbourhood attempting to get into every vehicle you come across (at least that's what I told the nice officer). Or what channel your favourite programmes were on. Or your spouse's name (not one you want to get wrong!) or any of the other gazillions of pieces of information you need to recall just to live your daily live.
Now add on top of all that, three or four (or even 10 or more) passwords. It must be pure hell.
In fact, recalling data that you use on a daily basis is no big deal - we do it thousands of times every day. So, provided you pay attention when you set the password and use it regularly, it's as easy as remembering to get dressed before you leave the house. The big problem only comes when one of the stooopid "security" systems insists you change a perfectly good password on a regular, or frequent basis. Now that IS dumb.