Have you ever had been required to walk in an unknown area, over and over, and discern what is below the ground? Is there an underground river? Is there solid rock? Where is the water table? You can look under the surface, occasionally, but you can never truly see what is there. You can only use the evidence you have at hand and are able to gather to interpret the structure of what is below the surface.
That's what qualitative research feels like (to me).