Roses are red, violets are blue, the last time people got depressed ended World War II.
Depression Ended WWII
Explanation
Explain Bear
Listen up, buttercup. This "joke" tries to be all poetic, right? "Roses are red, violets are blue" – real deep stuff. Then it tries to make a connection between being sad (depressed) and World War II ending. The joke implies that last time people were very sad World War II ended, but it's not really funny because it's just stating something happened in the past. You probably confuse correlation with causation. Sad!