Deja Vu

I was surprised that in a conversation on Deja Vu, 3 different perceptions came out.  One person felt it reflected real past memories to some extent, one person felt it repeats some vision of the future he had experienced vividly in a past dream or thought.  He believes this to such an extent that he claims he can make predictions of the future when deja vu hits him.  I have the consensus view that deja vu reflects the perception of a repeat event, but in reality, that past event did not occur.  

  - The FIRST version is a morphed version of the original concept; as in, someone says "looks like somebody's got a case of the mondays ," and you say "deja vu, you said that last week."  So it's an event that is actually repeated, but I don't think this is deja vu in the original meaning of the word.  

  - The SECOND person reflects a delusional understanding of deja vu, but probably one that many people share.  

  - The THIRD one is the standard interpretation that wikipedia  would provide.