I am going to throw away my extra food at work instead of saving it for later.
Why are you wasting your food like that?
I don't want to waste my food but I can't be bothered to finish it
You don't have to finish it all right now. If you wrap it up and put it in the refrigerator you can eat it later when you're hungry. I think that would be better than just throwing it away.
What's the big deal? It's just a little food?
Whatever you don't eat you can save for later. It's not good just to toss it away like that.