Nothing. It's just Rockstar has a thing that if you cheat, you'll never reach 100% completion, even if you do everything you can possibly do. You'll only be able to reach 99.9%.
"Growing up my dad was like 'You have a great last name, Galifianakis. Galifianakis...begins with a gal...and ends with a kiss...' I'm like that's great dad, can we get it changed to 'Galifianafuck' please?" -- Zach Galifianakis
