Want to take revenge from your friend by filling their mailbox with emails? Why not try the 'Mailbox flooder' to fill their mailbox with hundreds of emails. All you have to do is to specify the receivers email address and the 'Mailbox flooder' does the rest. It sends email with different titles so that your the receiver doesn't receive email in the form of the single thread.
You can also use https://projects.anomoz.com/projects/php/email_sender_try.php to test this program online.