I also have thought a bit about deja vu (although not quite as much as Kath has, wow! I think that post blew my mind!)
I agree there are different types of deyja vu!
I have looked at a theory for a while (similar to the mayan calendar) that maybe time isn't a straight line as scientists believe and is actually a huge cycle, like we are repeating things and that's why it happens. (Although that theory is kind of flawed and it was just a silly idea I had one day!)
Another type I think it may be linked to a past life, or perhaps you are tapping into the energies that other people have had there. I often go to places where I feel I have been before but sometimes it's just the energy of something memorable happening.
Brain lag sometimes but it's not accounted for all the time.
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