I'll go first. I recently did a seminar for my church on being safe online. I taught the group how to handle passwords, basic privacy and security best practices. After the talk one gentleman told me with some embarrassment how he "manages" passwords.
I'd never heard anyone say this nor would I have thought someone would do this. He had a draft email in Gmail where he keeps his passwords.
He told me, "that's bad isn't it?" Yes. Very bad.
So what's the worst you've heard?