Cereal or Bread

Two men walk into a grocery store to buy cereal

There are only two boxes left, but both are expired

Not wanting to go home with nothing to eat

One man picks up the spoiled cereal and purchases it

Only to come back home and have a bad taste in his mouth

The other man though refuses to buy either box

He has to go home hungry or ask a neighbor for bread

This goes on for some time as cereal sales plummet

Eventually the grocery store is forced to stock good cereal

Whose actions prompted them to make the change?

Did either of them have the right to complain about the service?