I wanted to steal one bag of Skittles but I ended up stealing the whole box
Is that how much you like skittles?
I like Skittles enough to risk getting caught
Stealing for any reason it not right and it is against the law. You need to be more mindful of your immoral behavior or you could get caught and prosecuted for stealing.
I don't think they would mind if I only steal one box.
They would mind because you didn't pay for it. People steal a lot so when inventory is taken, the business gets hurt by it.