BSG started out as a compelling drama set in space with some of the best space-fighter duels and cinematography on television. You could connect with the characters and thoroughly enjoy them reacting to the entirely plausible, yet gripping, situations in their battle for survival.
Then one day the writer woke up and realized that he didn't have any more material. Struggling against a hard deadline, he began taking LSD and recording his ramblings on camera. These ramblings eventually became script. Characters that were acceptable became objects of intense hatred (Starbuck). Characters worthy of great admiration became sniveling, pathetic, hams (Adama Sr.). Relationships and love became gut-wrenchingly awkward. LOST-esque plot twists pop up incessantly and you KNOW there won't be a satisfying believable explanation.
Cliffsnotes: Watch the first couple seasons and then stop abruptly.