I am a complete newbie here, but I LOVE Survivor, even though I haven't watched it right from he start and in order, because I am in Germany and it doesn't air here at all (not even a German version of it) But I am very caught up and love this ranking thread.

So ... for me I enjoy seasons mostly if I find at least one person I really, really like, the reasons for it being various. If I "fall in love" with one of the players, I get so invested in their path and how they do on the show, that this alone would cause me to rank the entire season higher. Also I love the "old" challenges like Survivor Auction and Endurance with Temptations and of course the locations play a role, I enjoy water challenges more than let's say the ones in Africa and I also love when the players have wonderful rewards and are invited to a tribal feast in a village of the local natives. I do enjoy when I find that people have a good heart.
Having said that, let's see...

~ Best seasons IMO (not in order, they all just rank as BEST for me):
20 - Heroes vs. Villains (because I love Sandra, she is my favorite player ever, her attitute is heartwarming and hilarious at the same time. She causes me to rank this season high dispite of Russell, who I don't like at all and never will)
7 - Pearl Islands (because of Sandra and Rupert)
12 - Exile Island (because of Cirie)
16 - Fans vs. Favs 1 (because of Cirie but also the craziness of gameplay later on, that was just great to watch, even though I felt for Erik!)
11 - Guatemala (I loved Brandon, Amy, Cindy and the entire tribe-dynamics which I haven't found like that again AND of course the location, which was just pure beauty, steeped in spirit and history (for me))
8 - All Stars (because of Rupert and because the tribe Amber & Rob etc. where on had so much fun most of the time (dancing and singing), which I rarely found later on, and for me that made it very enjoyable to watch.

~ Good seasons (not in any order):
10 - Palau (I loved Ian, didn't care much for Tom though, which makes me not wanna rank it higher)
9 - Vanuatu (Can't pick a favorite player, but the entire tribe dynamics made me enjoy it a lot AND of course, the location, that was amazing.
15 - China (same thing as with Vanuatu)
17 - Gabon (I loved the wild life aka Elephants so close by and also the winner Bob a lot)
18 - Tocantins (J.T., Stephen and of coure Taj! (I came to like Coach and Tyson more in their later seasons, not this one))
6 - Amazon (I really enjoyed Rob C. and Matthew)
2 - Australia (Because I loved how the people interacted with each other, I love when they are nice to each other to be exact, and these ones stuck together through so many tough times that it was just heart warming)
4 - Marquesas (I loved the "love-tribe" moments, also Paschal, Neleh, Kathy and Sean, he was hilarious)

~ Least liked Seasons:
5 - Thailand (Just didn't like any of the cast)
14 - Fidji (Didn't like concept nor cast)
19 - Samoa (because of the inroduction of evil aka Russell and making him and his ways such a horrible focus point all season)
21 - Nicaragua (Didn't like the cast, esp. Nayonka)
24 - One World (Couldn't stand Colton)
22 - Redemption (Didn't like how it seemed just handed to Rob while the other mates on his tribe didn't seem to have a mind of their own) AND also I just can't get on board with the redemption island concept at all. It cuts the beauty of rewards and plain reward challenges short and kinda contradicts "The tribe has spoken".

~ Things that ruined the joy of watching for me:
Russel Hantz (esp. in Samoa)
Brandon Hantz returning the way he did his second time around
Colton in "One World"
Redemption Island

I guess for me it comes down to this: It's one thing if I like someone enough to make me not care about the ones I don't enjoy watching (like loving Sandra which made it bareable to endure Russell in Heroes vs. Villains) but it is another thing if there is only Russell like in Samoa or Colton in "One World" with no one to make up for it (IMO).

Anyway, this was fun. I am looking forward to Febuary and hope to find someone to like in the new season