What do you do when you get bad food from the grocery store?

[Xithras]

So I'm sitting here a few minutes ago and I pulled out an apple to snack on. I bought the apples in a bag from my local grocery chain two days ago. I picked the apple up, took one bite, and discovered that the entire core was rotten. Dark, slightly moldy, and very disgusting. The only thing more gross than the sight of the apple is the knowledge that part of it was in my mouth. I can still kinda taste it. :puke:

Everyone has bought bad food from a store at one time or another. What do you do? Forget about it and drop the food in the trash? Take it back and demand a refund? Call them up and complain? Casually mention it on your next visit? Call a lawyer?

I'm not asking what I should do. I should take the bag of apples back to the store and demand my money back. But I won't, because I spent less than $2 on the bag and it isn't worth the time, gas, or stress to go exchange it. I'm asking what you actually do in these situations. Am I in the minority in just grumbling a bit and forgetting about it, or an I pretty typical? What would you be doing right now if you'd bit my moldy apple?