Good Riddles

Question: I can be flipped and broken but I never move. I can be closed, and opened, and sometimes removed. I am sealed by hands. What am I?

Question: When angry it turns red, cold it turns blue and pale when scared.

Question: Having some, you want more. But when you have too much of it you feel bored. Everyone people wants it, and some have to much of it. What is it?

Question: Having one, means having something to follow. Once you question it, it means having none. People seek it, but some do and some don't find it. What is it?

Question: Occurring once in a hundred years and once in thousands. But never in a day or a year or a century.