Unless you are a particle physicist, nothing.
The uncertainty principle states that the more precisely we know something's momentum, the less precisely we know it's exact location, and vice versa. But the value of the uncertainty is expressed in terms of Planck's constant, which is a really tiny number.
Essentially, uncertainty in momentum x uncertainty in position = half of Planck's constant:
Where Plank's constant
With very tiny particles, the uncertainty can be much larger than the particle, because the momentum and position approach the very small Planck's constant.
For large objects, like you and I and a baseball, the uncertainty in position would be far less than the size of the object, and as a result be inconsequential.