For me it's 2008. I had no problems watching this season, but the 2008 season made me stop watching and miss episodes from time to time.
Since I started watching in 2003, BB 2008 is the only series I actually gave up on and stopped watching (though I did watch most of it).
I often forget that Terri was the winner. I remember her about as well as some first evictees.
Kyle and Jackie O were a big factor. Pamela Anderson?
Fuck me gently with a chainsaw!
I might have said BB 2014, but this was the first year that I really got involved with this forum, and it enhanced my enjoyment so much that I will always look on it fondly.