How were computer users tricked into downloading email attachments?

Answer:
Downloading e-mail attachments that comes from an unknown source can be dangerous because the chance for hidden virus is high. But in most cases the users are attracted towards an attachment because they may come with beautiful titles and claims that they are good or highly useful in someways. A common type of such attachment is the greeting card attachments.
Sometimes they send people an email saying "Click here to upgrade" a program that they have and they download it
First answer by Sangeeth.S. Last edit by Bobskiebudgie. Contributor trust: 0 [recommend contributor recommended]. Question popularity: 1 [recommend question].