Wait really? It feels like almost every time I make a new account somewhere and drop in the 200 character high-entropy password that LastPass generated, I get a silent failure or misleading error message about "your username was not recognized." Then I try guessing which feature of my candidate password is pissing off the site: Is it the whitespaces? Special characters? Length?

This is particularly maddening because there are plenty of ways to accept arbitrary passphrases from users.