So, yes, people who had seen the first episode of Lost could see that the final moments of the series brought it all back to the beginning. (Stop reading if you don't' want to know how it ends.)
What you may not know, though, is how precisely Lost's producers constructed the ending. Remarkable.
A fan constructed this video, to prove his pre-finale guess that the final 108 seconds of the series would like very much like the first, in reverse.