I love season 1 but I was really, really, really mad with the death of Doyle. I know they were going to kill him off anyway but they got impatient and did it too quick. And the Scourge wasn't a good enough enemy!
Season 2 was awesome, with Cordy going to Pylea... 'Look! There's some branches over there in that patch of sunlight! ... I'll get 'em!'
Season 3 was ... interesting... I loved Birthday, which brought tears to my eyes with Doyle...
Season 4 was a mystery, and I adored the episodes with Faith and Angelus, which were brilliant. The episode 'Home' made me sob at the end with Connor (who I never liked) but it was still a good season with intrigue that made me need to watch every episode in one night.
Season 5 was hilarious and even though there were some weird and pointless episodes, they were funny. I especially loved 'The Girl In Question'.
In my opinion, all of the seasons, in general, were awesome. Some episodes I could've done without but all in all, awesome.
It ended too soon, I tell ya.