A series of books can be exponentially cooler than a standalone. After all, three times, five times, or even ten times the fun, right?
Or they can be three times more waiting, sadness (when the author, say, kills off your OTP*), and other extraneous emotions.
There's a cycle that, it seems, every awesome book series goes through. A pattern.
Stage 1: This looks good. I think I'll read it.
Stage 2: You're hooked. You may not know it yet, but you are. The book is awesome, and it's almost like it knows it. It knows it has you under its power.
Stage 3: This book. I like it. ANOTHER!
Stage 4: Now you have to wait for the next book. And wait and wait and wait and wait. But you're willing to do it quietly--for now.
Stage 5: Let people know how fabulous this series is. Tell the mere mortals what they are missing.
Stage 6: Release of the sequel. It's everything you hoped it could be, and more. Back into the fray!
Stage 7: Start shipping characters. You're well into this series now, and the rule of fandom life is as follows: when in doubt, ship it*. You're committed anyway; you might as well make the most of it.
Stage 8: Finish sequel. See the release date for the next installment. Ask yourself, "Why? Why me?"
Stage 9: Your sentence is to wait another zillion years for the next book. Accept sentence peacefully. For now, anyway.**
Stage 10: Lose all semblance of "waiting peacefully". Become desperate for the next book. Symptoms of this include reading any and all fan theories, sending angry letters to the author, ranting on your blog/Goodreads, looking at fanart, exclaiming "THE FEELS!", and more.
Stage 11: Repeat steps 6-10 as many times as necessary.
Stage 13: Now what do I do with my life?
Stage 14: Attempt to fill the void. Most likely, you will fail. But it's worth a shot.
Stage 15: Despite all the character deaths and emotions and waiting and general feels, it was all worth it.
**Is this a Titanic plothole? North Atlantic seawater is freezing, and when Jack is fully immersed at the end, he gets hypothermia pretty quickly, which makes sense. But why does he not have a problem standing in this water up to his knees? He stood there quite awhile. Shouldn't he have nerve damage or something?