This is so true. Smallville was my first open canon fandom - a good 20 years after I'd been in various closed-canon fandoms. And yes, the roller coaster ride of possibly being jossed every week, every season, that was a big adjustment. I finally had to stop watching SV when the direction they were taking Lex in became too painful for me to watch any longer. At least with SGA, everything's ending on a high note, there will be at least one movie (hopefully with the whole cast participating) and we get to write whatever further adventures we want.