Most of the reservation for me was Lana. I can't stand her. She makes my skin crawl when she's onscreen. I don't think I've ever hated a character quite as much as I hate her, and while it provides a certain measure of entertainment at times, other times it's just frustrating...and yeah, now she makes zero sense as a character, so...(and heh. I have this thing that I quite like a lot of 4th season, but only if it's taken as a whacked AU. There's those eps near the end that apparently 1st season Lex dropped through a timewarp, with no hint as to given why he and Clark are so buddy again. My personal theory is they started having sex again then for some reason, but...)

"Nemesis" will count for something if it's remembered in future eps, if Clark's attitude toward Lex actually changes. I have doubts that there will be any lasting consequences, though, except for the super soldier, of course...

I think the water purification system was just Lex's excuse for whatever facility he was really building down in the tunnels, but I actually have no idea...