Bill Gates was born Shirley Punchamaface. Unsurprisingly, he was bullied at school mercilessly.
As a teenager he took apart time job posting out invoices, or bills, for a local wrought iron gate manufacturers, in other words he would send the bill for the gates. Thus he adopted Bill Gates as his name.
Similarly, Melinda Messenger was born Agnes Wart-Deformity, and he first job from school was working as a morse operator for Mel Gibson, thus she became Mel's Messenger.
Mel Gibsons own birth surname was Schicklegruber, but he changed the surname to reflect his love of the Gibson EB3 bass, although he remained a raging antisemite.