...then I called my bank, they asked me what was my grand mother's name and I answered "Oh it's a very long, random string". I don't remember how secure the other questions were, but she seemed satisfied with such an answer (and granted me access).
In any case, I have 1Password generate pronounceable passwords specifically to avoid the problem of the rep trying to compare random alphanumeric strings. 1Password can even generate random phrases of N words (e.g. xkcd passwords) which works well for this sort of thing because it's easy to say those over a phone.
This is kinda the point though. We can cook up the most elaborate security scheme in the world, but ultimately the keys to our accounts lie with under trained, minimum-wage call center employees.
(EDIT: and hey, I've done some grinding minimum-wage bullshit jobs, I completely understand)