You should notice the grain, not the seams.
A floor done right pulls the eye for the right reasons: the run of white oak down a hallway, the veining in a stone tile, the way a plank shifts color as light moves across the room. What you shouldn't see is the work — a lip at a threshold, a gap that opened in February, a pattern that stops making sense at the doorway. That's all settled before installation starts, so the floor can simply be beautiful.