There's another post concerning a similar question, but after reading through it, I'm still not sure about the meaning of the sentence I encountered:
The calendar was blank, as it had been every day this month, except for the third Thursday, where she had scribbled, Civic Association Meeting. Molly sighed, remembering a time when every day had held a different list of assignments and chores, schedules for Erik, and important meetings for Cole. Eight years ago she had needed a calm, almost boring, lifestyle to save her sanity. Now, she wondered if she hadn’t let it go on that way for too long.
Was Molly regretting that she had let herself live "that way" for too long, or was she missing being "that way" when she found she had nothing to do?
Best Answer
Barid glossed over this, but I think this is the real only answer. Consider the difference between:
"Are you supposed to be at work?"
"Aren't you supposed to be at work?"
"Do you have a dollar?"
"Don't you have a dollar?"
"Well, is that special?"
"Well, isn't that special?" (See Church Lady)
"Has this gone on for too long?"
"Hasn't this gone on for too long?"
They are not exactly equivalent. That negative suggests the speaker thinks you are supposed to be at work, you do (or should) have a dollar, that is special, and this has gone on too long, and is offering you the chance (or daring you) to deny it. Putting "wondered if" in there makes it a little gentler, but she is not feeling neutral about the question. Her internal dialogue may well be, "Haven't I let it go on this way for too long?"