With the spread of viruses and malware, most users are very aware of the importance of such things as not opening unknown emails.
However, along with these, there is a proliferation of hoaxes that are sent out. Typically, these have dire warnings about a new virus that is spreading, and to pass it on to all of your friends. Usually, they also include some statement about how this has been confirmed by Snopes, or Microsoft, or some other big name in the computer industry.
While being aware of new viruses is important, spreading these hoax messages is detrimental. It increases the amount of email people have to go through. Overall, I feel that it desensitizes people to the importance of virus protection. If someone keeps getting these false warnings about viruses, then they are less likely to believe, and act on, genuine warnings.
So, check out the validity of virus warnings that you get. They can usually be checked at your virus software Internet site.