The most important part of confirming your email is to be 100% certain that you use the email associated with any service you've chosen, like PayPal or Amazon. If you've chosen an eGift card, or bank deposit, then you only have to make sure the email is correct.
It's important for services like PayPal and Amazon that you use the email associated with that account, because otherwise you might not be able to get the funds into your account.
In some cases, you might be able to add an additional email later if you made a mistake, and here's the information from PayPal on how to do that, in case it helps.
