A sound of thunder, by Ray Bradbury, is about two men going into the past to kill some dinosaurs. When they go back they have to follow this floating path. If they step of it, it can cause a change in the future. So when they go back in time, and one of them sees the dinosaur. He freaks out and runs back to the teleport spot. He accidentally steps of the path. He does not know it yet but that action has changed the future drastically.
After he came back to the present, he found that he stepped on a butterfly. In the present a election was finished but they find out that the winner was changed. That ruler was a dictator and was described as a anti-everything person. And the spelling was changed on a sign and things were all weird. After finding this out the other man shot him in the head.
I think the main theme of this story is that all your actions have impacts on the world either long term or short. Even though the butterfly was so small, it had such a big impact on the world by killing it. An example of this in the real world is that you can slack off and not study but that just might make you not smart enough to get the the job you want.
What I took away from this is that you shouldn’t slack off and that even the smallest details of what you’re doing can still make make a impact short or long term.