Best Riddles and Answers

Question: You see us everyday, but you never see us together. We appear everywhere but never are we together at the same place. Who are we?

Question: I can be seen, I can be not. Thanks to me, you'll fall in love. I mostly am sweet, but once I were sour. You can receive me, you can't just buy me. You only can send me, or simply share me. What Could I be?

Question: Why did the boy throw the butter out the window?

Question: 8,549,176,320 What makes this number unique?

Question: What is so delicate that even mentioning it breaks it?