I've run into the problem of web services not letting me store passwords. The reality is, if you let my password manager (safari jacks into OS X's keychain system) keep track of things, I'm going to use the random 12-digit alphanumeric password my password manager provides me. If you don't, I'm either going to use my shitty "brain" password or put it in my password manager anyway and just copy-paste it manually.

Thankfully, safari on both iOS and OS X has a toggle to ignore autocomplete=off, which I take advantage of liberally.