I Have a Serious Writing Problem…

I was working on my query letter this morning, tinkering with the wording because I have it almost where I want it when I was struck by a thought:  this query letter is better than my book!  I’d better make my book just as good!

So, I began tinkering on my novel again….my finished novel–at least what I had previously thought was finished.

I have had this problem with all of my work.  It’s never finished. I’m constantly tinkering and it drives me up the wall!

I’m wondering if anyone else has this problem.  Just now, I was tinkering some more (well, since I had already started, why stop now?).

I can’t stop myself.  I tell myself I’m done.  Then I’m at it again.

So, I’m wondering:  Is a novel ever finished?  And when?  When it’s in print and you can’t make any more changes?  This I see as my scenario.

Any comments would be most welcome (especially ones saying I’m not crazy!).