Sticking the Landing

Welcome to the first Wednesday of the month. You know what that means! It's time to let our insecurities hang out. Yep, it's the Insecure Writer's Support Group blog hop. If you're a writer at any stage of career, I highly recommend this blog hop as a way to connect with other writers for support, sympathy, ideas, and networking. If you're a reader, it's a great way to peek behind the curtain of a writing life.

Our Twitter handle is @TheIWSG and hashtag is #IWSG.

The awesome co-hosts for the March 2 posting of the IWSG are Janet Alcorn, Pat Garcia, Natalie Aguirre, and Shannon Lawrence!
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I'm trying to write the final book in my Menopausal Superhero series right now, and it's kicking my butt. It seems ridiculous, feeling frozen after four novels, 2 novellas, and a selection of shorts. 
Maybe it's the finality of it. 
This is the end, my chance to wrap it all up, and bring it together in a satisfying way, freeing myself to work on all the other projects that have been calling my name while I forced my focus down this one path to see it through to this moment. 

And now that I'm here, I'm suddenly full of doubt. 
What if I can't stick the landing? What if I took myself and my readers on this wild ride only to write that ending fails? 
It's silly really. My publisher wouldn't let that happen. If I turn in a draft that doesn't do the job, they'll help me with some development edits. But first I have to give them something to edit, and that's where I'm stuck. 
So my questions for the IWSG community today: 
1. If you've finished writing a series, how did you wrap up it up? Any advice to make sure it satisfies?2. What series have you read where you either LOVED the ending or were frustrated by it? Why? What makes a good series ending? 
Or if you don't have any advice, sympathy is also appreciated! It's a good problem to have, I know, but I still need to solve it.