A couple years ago when I was writing my first honest-to-God attempt at a book, I kept encountering the same problem. I'd go through writing the parts that excited me, and put placeholders for the parts that I knew I wanted in there, but didn't necessarily feel like writing.
At one point I lamented to Hubby about a particular scene I was procrastinating on because I thought it would be boring to write. His response? "If you think it's boring to write, maybe it'll be boring to read."
Duh. Why didn't I think of that? Because I didn't. The thing was, I thought of these scenes as necessary to move the plot forward. I didn't look at them as having any value themselves. Just segues between the "good" scenes.
Here's the thing. Every scene should count. No, wait. Every paragraph--hell, every word--should count. There shouldn't be a point in your manuscript where the reader gets bored, wants to skip ahead, decides it's a good time to put the book down and have a snack, etc. And the best way to judge this is to truly love what you're writing. Be your own fan. Laugh at the funny parts, cry at the sad ones. Go ahead and fall in love with the romantic lead, give your MC a mental fist-bump when she does you proud. Because to paraphrase from Hubby: if you don't want to write it, you can be sure as sh#t that nobody is going to want to read it.
(See how much I've learned? And I'm documenting it all for you, so you don't make the same mistakes, fellow scribes!)