early 2000s show is that was mentioned

"Verrrrrrrry popular show" narrows the possibilities. "First season was brilliant," but later "making it up as you go along ... contradicting stuff...", "F-U to the audience" — My guess, they may have been talking about LOST (which in its time was indeed "verrrrrrrry popular" lol).

Although some ardent fans of a show such as LOST (especially the most zealously and emotionally invested fans who considered it "perfect," "flawless," "the greatest story ever told") were known to defend against any and all criticisms — insisting that the show's plot developments, although not all pre-planned, were never truly contradictory; that the show never really left any really significant questions unanswered; that the writers and showrunnners never disrespected the audience; and that the show ultimately achieved flawless perfection at the pinnacle of human creative achievement, "the greatest story ever told." lol...