I liked seeing Captain Archer learn the lessons that would lead to the Prime Directive. Trip was a fun character, and I liked his romance with T’Pol. There were lots of good individual episodes, like the one about T’Pol having Vulcan AIDS, and Shuttlepod One. Any episode Commander Shran was in is great, especially the episode that Archer duels him. Jeffery Colms is the best. Brent Spinner was also great in his little arc. And, I legitimately liked the Xindi.
That said, the timing of the Xindi arc, in the middle of all the real-world stuff going on, was bad, and it had a bad message. I also did not like all the sexual stuff, especially the episode in season 1 where T’Pol gets forced into Pon Farr by a virus, and tries to have sex with everyone. And then just, like, the whole last half of the last season. Mirror Universe, gross. Trip and T’Pol’s baby dying, sad. Riker’s Holodeck cameo finale, disappointing. Fuck Berman.