Sometimes I might have an image in a dream that just flashes for a second, or I do/look at something in the dream. Then, sometime during the day I will just freeze up, realizing I'm looking at that particular image or doing/seeing that thing.
For example, I dream that I'm sitting on a park bench looking at a sign. Afterwards, when I'm awake, I (unintentionally) go to a park, sit on a bench and look at a sign.
It's not typically something like that. Normally, it's something I would never go out of my way to do. But when it happens, it's freaky.