[Bluefields]

Riverkid, nice to have you with me. Your examples are bang on, but it's not clear how many are convinced.

Here are a few more comments.

"Only" is necessary to express regret only where there's no question of obstinate refusal. Otherwise, "would/n't" achieves the function unaided, and needn't include the meaning of habit.
In my previous post I used the term "obstinate refusal" and thought that to include in this annoyance at one's own bad habit was unproblematic. Apparently not for everybody. Could I have avoided the problem by changing O.R. to "regret" ? Not quite.
We have "would" sentences expressing O.R. (obviously including regret), and "only" sentences expressing regret but no O.R. (the hammer sentence). But by my intuitions, even if it is somebody's fault you can't use "would" without O.R.
"If you would have lent me the money,..." is O.K.
but not
'If you would have remembered to bring the hammer,..".

Is this a problem for the poll sentence ? Maybe changing O.R. to "regret at refusal" helps a bit. Then it all comes down to whether regret at failure to give up one's own bad habit is similar enough to regret at refusal to give up one's own bad habit.
It works for me. Grammatically and semantically sound, and we're talking about expressing a strong emotion, annoyance with yourself. If the speaker sees it this way, he can so.
Tdol, I can't see why more context is needed for the 1st. person, but might be convinced. Can you elaborate ?