Distillation process - the basics

I know boiling chips are used to prevent bumping of a mixture, but...

1) What would be the reason a student has bumping in a flask, even with boiling chips?

Regarding distillation in a general sense...

2) Why is the direction of water flow in the condenser important?

The cold water must flow in the opposite direction to the flow of vapor/liquid. Heat is exchanged in the condenser tube and in order for the vapor to continue to condense flows through the condenser tube it must exchange heat with fresh cold water.