[Aliska]

What would be the result if this happens? Bad things?

Nah. Just that your bathwater will swirl the other way when it goes down the drain.

[Wrigley]

We'll have to drive on the other side of the road too, right?

It could also mean the Cubs will win the World Series in the near future....

[Maelstrom]

Cut it out...someone might believe you. The Coriolis effect(which way the water spins in your toilet) has nothing to do with which way is north.

[Bloody Sam Roberts]

"Nah. Just that your bathwater will swirl the other way when it goes down the drain. "

That has to do with the Earth's rotation and nothing to do with the Earth's magnetic field.
But, you probably already knew that.