It usually takes some kind of achievement or trophy you can show off to your friends to compel people to 100% complete a video game. For Steve Tolin, however, all it took was the pursuit of true completion.
That and 773 hours of his life.
Tolin has completed 100% of Dragon Quest IX's content, the DS game wrung bone dry in pursuit of completed post-game challenges and items like the infinity trousers.
In a neat touch, after completing quest 184, a congratulatory message from Dragon Quest creator Yuji Horii appears.
You can read an interview with Tolin at Tiny Cartridge, linked below.
Tiny Q&A: Dragon Quest IX 100 percenter Steve Tolin [Tiny Cartridge]