Tell the cook of this restaurant with my compliments that these are the very worst sandwiches in the whole world, and that when I ask for a watercress sandwich I do not mean a loaf with a field in the middle of it.
You may choose to include some music, if you think/know, that the receiver is able to play it.
Put receiver's email address in the first field. You may supply more than one email address, as long as you separate them by comma. Put your own email address in the second field, eventually type a message to the person, and click "Send".