What is the reality of the phenomena?

Let's take it from 1933 with the Magenta UFO crash in Italy or the Roswell UFO crash from 1947 to today. The phenomena looked like it switched gears. First we had these encounters with aliens that looked different from the actual gray type. In these encounters, the witnessess tell a different story from what we have now. For example, they're shown the spaceship, they're been asked how to get to a certain place, how to get X materials, they take samples and they typically say they'll come back...