In all seriousness: Season One of Justice League was hit or miss for me (a fact that Bruce Timm and Dwayne McDuffie agree on). It had it's moments (Injustice For All, The Savage World) but it had a lot of filler.
But season two?
Darkseid/Brainiac team up (Twilight), The Amazo and Dr. Destiny episodes (Tabula Rosa and Only A Dream), Grundy's death (The Terror Beyond), The Secret Society, Alternate Universe Justice League fukking shyt up (A Better World), Superman's "death" (Hereafter), Joker being a formidable foe for the JL with The Royal FLush Gang (Wild Cards and one of the best Batman/Joker fights ever) , and of course Starcrossed.
Then, they just upped the ante in JLU with the Cadmus story arc which is one of the best arcs in the DCAU. They also had a lot of good stand alone episodes (For The Man Who Has Everything, The Cat and the Canary, This Little Piggy, Kids Stuff, Double Date). And Epilogue - the true season finale to Batman Beyond
. So much piff for one episode. I'm surprised it could handle it.
Season 3 of JLU, while a bit of a step down was also piff with a lot of great Flash centered episodes (Flash and Substance and The Great Brain Robbery) and not to mention the finale with Darkseid returning and the LOD and JL having to team up to save the world.
So much awesome sauce.