I was unhappy with my job, so I submitted my resignation. I was sure I'd have no trouble finding a new position, because there was a shortage of people with my skill.
I e-mailed cover letters to dozens of potential employers, attaching a copy of my resume to each one. Weeks later, I was dismayed and bewildered that I hadn't received even one request for an interview.
Finally I received a response that explained it all: "Your resume was not attached as stated. I do, however, want to thank you for the vegetable lasagna recipe."