I emptied out a box of Lucky Charms onto the table, took out all the marshmallow pieces, and then put the plain cereal back into the box.
Why would you do that to the cereal and are other people going to be eating out of that box?
Yeah. It's the box of cereal my family uses. I did it because I wanted the yummy marshmallows.
Taking out all the best parts of a box of cereal just to keep them for yourself is rude and selfish behavior. It denies other people the enjoyment of eating that cereal. You should not steal those pieces and instead just leave boxes of cereal untouched.
I wasn't thinking.
It sounds like you regret what you did, and that's good. Doing something selfish like taking the best parts of a cereal is going to make people angry with you. You should apologize to your family for what you did so they know you are sorry.