isn't that sad

It was a fun day today. We had a nice big party. And everyone at school was having a fun time. Then i saw i teacher walk by me. Smiling all happy from cheek to cheek. The biggest smile ive ever seen. Then i was struck. What if something were to go wrong. Dark thoughts flooded my head. I was thinking bad things on such a happy day. I scared myself. I thought of how fast that smile could be taken away. Seconds. I dont know how i could think of something so horrible. So unforgiving so ugly