I don't really get flashbacks per se, but deja vu does occur quite often.
For some reason this also reminds me of another thing that happens a lot: Ever watch someone eat a Warhead, or you're about to eat one yourself, and as you're thinking about that warhead being in your mouth, your tongue suddenly explodes with a soury taste, even though there is nothing in your mouth (world's longest sentence)? I love that. It happens every time I'm about to eat some ice cream or sour stuff, without fail.