This seems like one of the simpler solutions on here, what's your process of dealing with sites that require special characters etc?
The problem is, the login form doesn't remind that a) a special character was required and b) what characters that particular site thinks are "special".
(Data: I have 72 logins currently cached in Firefox. Every single one of those sites accepts 10-character mixed case alphanumeric passwords with no extra special character requirements. About once a year I come across a site that needs one.)
Still, I'd say it's inconvenient to have "special cases" to remember about. Even if they're something important, like banking.
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Someone had mistaken downvote with "I disagree" rather than "unhelpful". Upvoted you, as I think your comment was helpful and contributed to the discussion.
But this is going off-topic (and discussing votes is something we should refrain from)