iOS 8 introduced a new predictive text system as a feature of the new keyboard. I hate it. Maybe if I gave it a chance it would help me out but to me it's a huge distraction and instead of thinking about what I'm typing I end up evaluating and asking myself "is this the next word?"While you can simply pull the grey bar down to hide it or push the slim hidden bar up to restore it, I like to take things a step farther and remove it completely. Go to Settings > General > Keyboards. Turn off "Predictive". Now the predictive box will be gone and you won't accidentally enable it again.
iOS 8 tip: Completely disable the new predictive text
