system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do all dumpsters smell the same?
gpt
You're not smelling the trash, you are smelling the waste product of micro organisms that are eating the trash. Since all microorganisms have more-or-less the same goal (get energy from food source) they are going to generate similar waste products in doing so. This is especially true for microorganisms feeding on similar materials, in this case trash. Your body doesn't want to eat food with microorganisms that might make you sick, so humans evolved an aversion to the smell of microorganism waste. Since there is no benefit to being able to distinguish between the waste of one microorganism from that of another, it kinda all smells the same to us.