strange things only I notice

When you use Outlook for your email, and you type in an email address in the To: space....you know how it tries to complete the email address for you? Like if you type in an "A", it will come back with all the email addresses of everyone you've emailed that starts with the letter A.
Well, I've been using my email account at work now for over a year and a half. And, I send a lot of emails to customers, co-workers, friends and acquaintances. And in all that time, I don't have any emails listed under the letters Q or Z. Which means I don't know anyone who’s email addresses start with Q or Z. Each of the other letters of the alphabet, I have at least 2 listings. (Yes! I have 2 listings under X!!). Huh!