Made it over to iOS 7 yet? Inside the flat, white-background Messages app, you'll notice that when Richard Smith sends a text, the conversation list and back-and-forth conversation shows just "Richard." The same plain "Richard" goes on top of chats with Richard Jones, Richard Appletree, and all those other Richards with whom you stay in touch. Need more detail?
Allyson Kazmucha at iMore finds the setting for Apple's first-name-basis in a place you might not expect. As detailed at iMore, head into the Settings app, then into Mail, Contacts, Calendars. Scroll down to the Contacts section, tap the Short Name field, and decided if you want to turn off the Short Name switch entirely and see full contact names, or choose an option: First name and last initial and vice-versa, first name only (which is what you're trying to get away from), or, for all the gym coaches and drill instructors out there: last name only.
Simple but tucked away. Have a good weekend, knowing your coworker Bob and your father Bob will not receive your confusingly misaligned sentiments for each.