I exited my time machine and saw my kitchen and dining room. A sandwich stood on a plate in the middle of the table.
"Sweet, I made it," I said and went to the table. I settled in a chair and took a bite out of the sandwich.
"What the fuck!" A familiar voice yelled. I looked up, and my heart sank as I saw myself standing in the doorway.
"Who are you and why are you eating my perfect sandwich?" He (I?) shouted at me. I shrugged.
"I'm you from about... twenty minutes from now," I said. "Some asshole came from the future and stole my sandwich too. So here I am, stealing your sandwich because I couldn't eat mine."
"I dare you to break the paradox," I added.
"And have two of us competing for food, not a chance!" He said and ran to where the time machine was kept before we used it.
"More for me, I guess," I said and kept eating.