I've come to realize I have serious commitment issues when it comes to book series. I have a really hard time reading a complete series. Even series that I like! One that comes to mind is Gail Carriger's Parasol Protectorate books. I adored the first installment in the series -- I think I even gave it a 5 star -- but I've never read any of the others in the series. My list of unfinished series grows by the day.
I think there are serveral reasons for my bad habit.
1) I am a slow reader. This may sound crazy, especially considering I was an English major, but I have always been a slow reader. During college, I always tried to get the syllabus as soon as possible so I could start chunking away on the required reading. If I didn't start early, I couldn't get everything read.
2) There is just so much good stuff out there. Once I read the first book in a series, I'm anxious to get onto something else new. Every day when I read book blogs, there's almost always a review that makes me go WOW, I want to read THAT! There's no way to read everything that looks good, but at least by reading the first book in a series I get a wider sampling.
3) I love to learn. This ties into #2 in a way. Since I am always learning and improving my own writing skills when I read, I like to expose myself to as many different books and writers as possible. I don't feel like I am learning as much when I get to Book 6 of a series. A lot of the techniques found in the first book of a series can be found in the rest.
4) There are very few series that I love to the point where I feel compelled to finish a series. In the past 2 years, I can only think of 3 series that I loved this much: The Hunger Games by Suzanne Collins, As the World Dies by Rhiannon Frater, and Mistborn by Brandon Sanderson. (I would like to add Penryn & The End of Days by Susan Ee, but she only has 1 book out in her series so far.)
Maybe this all boils down to me having a short attention span and being super picky? Am I alone in this? Generally speaking, do you guys finish an entire series when you start it?