Most email today is spam, unwanted commercial email, or phishing, fake email designed to separate you from your money. Criminals routinely send fake emails that try to get you to tell them your log-in information for your bank or your PayPal account, so they can steal the information, log-in as you, and steal your money. It is very easy to fake a return address on an email, so simply looking to make sure that an email has a valid sender is not sufficient to ensure that the email was actually sent by the person or company that claims to have sent it.
