See if the drilll operates
See if the drill bit is running true
Make sure the chuck key has been removed
Non of these
Reem the hole slightly larger
Give the drill operator better drilling leverage
Help keep the hole centered
Reduce overheating the drill bit
The bit will break
The drill will twist in the operators hand causing a sprain wrist or bruised fingers.
The drill will likely stall out or overheat
The hole will become badly distorted
Make the final hole drilling operation easier
Guide the final drilling operation to achieve a more accurately placed hole
Reduce the feed pressure needed to drill the hole
Allow the final hole to be drilled at a faster RPM and achieve a smoother finish.
Reduce the RPM's of the portable electric drill
Lubricate the drill bit
Use a high speed drill bit
Reduce the feed pressure when the bit is about to come through the material being drilled
Here's an interesting quiz for you.