He Who Knows You

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: What has a bed that you can't sleep in?

Question: What cannot be seen or felt, but can only be broken by voice?

Question: What tastes better than it smells?

Question: What goes in the water black and comes out red?

Question: What asks but never answers?