Good Riddles

Question: In Colorland, there was a party. Red tried out the hardest adventures and he was never scared for his color, red, symbolized courage. Orange looked at the sun with a smile for his color is the color of the sun in space. Yellow went on laughing for her color symbolizes happiness. Green went on in the fresh grass for grass is his color. All the colors were happy. However, Blue stared at the horizon, crying. Why he is not happy?

Question: When I come in, someone else leaves, I know everyone, yet no one knows me. I'll meet you all only once in your life, Causing mayhem and mischief and sorrowful strife. What am I?

Question: An item looks square from outside, Circle when opened and Triangle when taken out.

Question: Two cops walk into a doughnut shop. One gets a sprinkle doughnut and the second one gets a sugar doughnut. What did the third cop get?

Question: You're stuck in a room with no way out, no windows, no doors, and no roof. All you've got is an apple and a knife. How do you get out?