People are good at evaluating the risks of sharing personal info with other people.
The real problem is people sharing the same password between multiple sites. People are really bad at evaluating the risks of any given website being hacked and thus making all other sites that use that password hacked as well.
The best thing we can do for security is encourage to write their site-unique passwords on sticky notes and post them clearly and legibly on their monitors. We'd go from millions of people being compromised every day by malicious hackers with a means of really messing you up, to one or two being hacked a day by someone's brother wanting to pull a prank.
Once people make 10 unique passwords, they'll switch to a password manager. But even if they don't, you're safer printing your username and password on a t-shirt than you are re-using the same password on both google.com and adobe.com.