Writing Is Hard Work!

It's been a while since I've posted, sorry about that, but the edits for the next Vinnie Esposito series novel has taken priority over all else since it is due to be released in September. SURPRISE!!! (to me, too) I have been working on the edits to get them in on time. But, I digress as to my subject today...
I have to laugh every time I hear the words, "Oh, you work at home". Does everyone think writing is easy? That working at home is a breeze? That you aren't interrupted every other minute? That you consider running away sometimes? Gosh!
I usually smile, grit my teeth and say, it is a "real" job even though many don't seem to think so. That statement usually draws attention and lets the speaker know I'm not amused at the comment.
Writers, any type, work long hours, are often paid little until they become well known, and in many instances they hold jobs that keep the money flowing in the door. (It is difficult to write well when you have to live in a box under a bridge.) I can say that I do get reprieves every now and then by heading into the studio and slapping some paint on watercolor paper. It is rewarding, renewing and fun to say the least.
I have a question for you, though. I have a novel I've been working on for about three years as a tweener (in between the others that are under contract), and for the life of me I can't seem to write The End on this piece of work. Do any of you have this problem when it comes time to finish a project? Any Project? Why?
Let me know, I'd like to gain some insight on why I can't get 'er done.