It's ok, I understand. I get things wrong all the time.
Seriously. Season 4. Jack takes on a fucking whole compound of guys to save Heller. Palmers in it. Logan gets introduced and has a great run in it. The Chinese Embassy thing is great. Audrey isn't annoying. Tony and Michelle are in it. A good EMP subplot and decent firefight after. An element of almost finality and closure with the ending.
Season 6 has...?
I don't hate S6. It's slow and Jack is all but twiddling his thumbs in parts but it also has some of his highest highs("Damn Jack...") along with tons of MGS parallel, but it isn't in the same league as S4.
S4 is the most fun, most rewatcable season of them all imo. It features an all-star roster of 24 greats not to mention non stop ridiculous fuckery from beginning to end:
-Jack robbing a bumfuck gas station and taking a terrorist hostage
-Tony day drinking and watching soccer while being emasculated by his sleezy girlfriend
-Tony running CTU hours later
-Tony back with Michelle hours after that
-Araz family drama highlighted by Dina poisoning Behrooz's stalker girlfriend while showing her baby pictures
-Edgar computer scienceing the shit out of nuclear meltdowns
-CTU using sensory deprivation to torture Sec. Heller's poor hipster son out of the closet
-Paul Reigns allowing himself to be tortured with a hotel lamp so Audrey feels sorry for him
-Jack leading redshirts to victory over a private military force
-Mandy wreaking utter havoc on an apartment complex
I could go on. And while he was no Henderson(or Saunders or Drazen), Marwan was a worthy a villain.