I got into supernatural kind of back works. When the show started I was done with Smallville at that point, not amount of clex could have saved it for me and in turn I was done with the WB. But almost all my f-list was watching Supernatural so I knew the storyline/characters etc. I had seen a few episodes even but RL was more demanding then fandom. Then season 4 happened. I had heard about the grandeur of season 3 and decided to give the show my full attention and I was hooked. I went back and watched the past seasons in full to get completely caught up and now Dean Winchester is my fav character (he was so gorg in the s4 finale, all those close-ups on his eyes and freckles *fans self*).
People talk about how the show needs to die already or that its strayed from the idea of being about "the brothers". On the first, all shows have an end point and with the world building in supernatural it's kind of an open road. As far as the second, other characters and plotlines will come and go but the core of the show is always Dean and Sam and their connection. They have been through the wars together (literally) and made/lost friends along the way. They're family and nothing/no one comes between that. I like castiel and find his interactions with Deanrunning the spectrum from intense to funny. They have a chemistry and an connection that's different from dean & sam's but it doesn't detrack from that and I also think it gives Dean different dimensions the same way that Sam and Ruby's or Sam and Lucifier's interactions showed different aspects of Sam. It all comes back to the core relationship and strengthens it in my opinion.
The new season sounds interesting though so I'm hoping people will give it a chance. Especially since rumor has it Bobby my be getting some this year O_o!