You are one data breach away from having your entire online life turned upside down. The problem is passwords, which are hopelessly fragile ways to secure valuable resources.
Don’t be lulled into a false sense of security by the belief that creating a longer, more complex, harder-to-guess password will somehow make you safer online. You can create a password that is so long and complex it takes you five minutes to type, and it will do nothing to protect you if the service where you use that password stores it improperly and then has their server breached. It regularly happens.
And even with reasonable policies in place (complexity, changed regularly, not reused), people are still the weakest link in the security chain. Social engineering can convince even intelligent people to enter their credentials on a phishing site or give them up over the phone.
The solution is two-factor authentication, or