In a lot of manuscripts there are sad or hard parts. Sometimes lots of them. There is tough stuff we know we have to write, even if it makes us cringe (or ugly cry). And even though we don't want to do it, we do because we have to tell out stories.
A good friend quoted to me recently, "you either write because you have to, or you don't write." That's so true. I have to write, so I do it, even through the hard to write parts.
But the hard parts also refers to the hard parts of life. If you gave to write though the hard parts of manuscripts you also have to write through the hard parts of your day, week, years. I'm butting heads with a particularly hard part of my life right now, and I'm making sure to push through all hte words. I've stayed with my goal despite wanting to just wallow and sleep. I wrote 6k this weekend, and it helped me get through the tough stuff is rather ignore, because I HAVE to write. My stories need writing through the hard scenes and through hard life moments.
There are a lot of things that go into being a good writer. I've heard, and believe, "editing makes the difference between a writer and an author." Another one I love by is, "every story had a reader." But even more than those I believe that writing through the hard parts is key to being a good writer.
The hard parts of manuscripts and the hard parts of life make a writer stronger, better.