My father, the computer genius:
"I got this from a person I know, is it safe to open?"
"No, dad, double extension (.xls.exe) and nonsensical body of the email usually means virus."
"But... I know the person who sent it to me. That means the email is safe, right?"
"Dad, it's a virus, trust me on that. You aren't a living antivirus program, shielding everybody you know from virus infections."
"But..."