Something worthy of positive acknowledgement is said to exist.
Synonyms: rule, kick ass

Something that used to exist, but now doesn't.

A word that should be removed from the dictionary.
Something exists, but if no one believes it does, then it does not, even if it's actually there.
Something does not exist, but people believe it does, so then it does, even if they can't prove its existance.
Crazy people...

something that you are forced to do every second of your life.