What was the most difficult promise you made?

For some reason I've found people's answers to today's question fascinating.  I've noticed that several people say that keeping promises to themselves is challenging, because it's easy to let things slide, and nobody else will know.  And I can certainly agree with that.  That's one area where "dieting" actually taught me a positive lesson at a relatively young age, because I realized that I can intend to do something, but that doesn't mean that I will actually do it.  The positive side of that lesson is that I don't make "promises" to myself.  Instead, I work from my values.  I don't want to compromise my values, so I weigh what I am going to do in response to particular situations, but I don't make blanket "promises" to myself that I will do or not do things. 

For me, the difficult promise is "for better or worse, in sickness and in health."  What, exactly, do these two phrases mean?  Certainly there are boundaries to these statements.  As an extreme example, nobody would expect someone to continue with a partner who is dishonest and abusive.  But many relationships are moored somewhere in a gray area--not even gray by intention, neglect or incompetence, but gray by virtue of time, luck, changes of the wind and sea.  In my case, he is unable to remember making these vows, and still we stay the course.  In any case, things would be completely different now than they were 25 years ago.  This is a really difficult thing to learn about, and I'm grateful for the lessons.