Your password is the key to your account. If someone knows your password, they can use your account - and you'll end up paying for it. You wouldn't give the keys of your house to a stranger, would you? Protect your password in the same way. It's as simple as this - Never EVER give your password to anyone!

For added security, you should also make your password hard to guess (combinations of letters and numbers are best) and change it regularly.