Even for people who view low-carb as a lifestyle, not a temporary diet,
there can be challenges.  What happens is, it's Halloween and you have
all this leftover candy because you only got like, 2 trick-or-treaters
this year, but they're the mini-sized bars so you can have just a
couple, right?  And just a couple the next day, and so on, and you think
"As soon as this is all gone, that's it, I'm back to low-carb" but then,
surprise!  Thanksgiving shows up.

So you go and have Thanksgiving dinner with your family, and you're all
"Hey, it's just one meal" but then they send you home with leftovers,
because they love you, and their love takes the form of mashed potatoes
and green bean casserole. And then before you know it Christmas is here
and everyone you know and apparently everyone THEY know is giving you
chocolate, and it's not the crap kind from the drug store either, it's
the good stuff, so you'd feel awful just throwing it away or regifting,
because they went and spent all that money on you.

Oh, and if you're Jewish, you have to have some latkes at Hannukah
because your 80 year old grandmother made them and she'll cry if you
don't eat some.  

And then you go to a New Year's Eve party with all the booze and the
munchies, and so by this time your cravings are back. You make a valiant
effort to get them under control again, and just when they seem to have
all but vanished, a box of Valentine's chocolates will somehow
materialize in your life.  

But hey, you're just at your winter weight, right? And you'll lose it
again soon, no problem.  But the thing about winter is, it's cold. And
snuggling under a blanket with comfort food just seems so . . . well,
comforting.  And besides, it's cold!  So you can live in your big bulky
sweaters and no one will be the wiser!  And you know you can quit the
carbs any time and lose the weight again before spring.

But time has this way of passing when you're not noticing, and all of a
sudden the stores have bathing suits for sale, and you look down at your
bloated body and bemoan to the world "Wait!  Not yet! I'm not ready!  
This is just temporary, this isn't what I really look like! It's not
faaaaaiiiirr. . . . "  

And so you come crawling back to low-carb, tail between your legs,
promising you've learned your lesson and asking for just one more
chance, this time I'll stay, I mean it, I won't disappoint you again,
come hell or high water or latkes or chocolate, I will remain faithful
no matter what.  See?  I bought broccoli, and steaks, and fish, and some
of that cheese we like, and nothing chocolate at all, see how much this
proves I'm back for good?  Look, I'm eating a salad!  With grilled
chicken!  And I like it and I don't want donuts at all, I swear!

Not that any of the above applies to me, I'm just guessing as to what it
might be like.

It's hard to say what will cause this connection to "click" in a person.  
I had lost and regained weight several times over the years, but never
had the mindset to do it right until I tried Atkins.  It's not as if I
hadn't heard all of my LIFE that once you go back to eating "normally"
(regardless of which diet plan you try) you'll gain the weight back, yet
it never gained a permanent foothold in my brain as far as accepting
that as a fact of life that I had to abide by if I didn't want to gain
the weight back.  So each time I lost I eventually regained and went
higher and higher each time.  

Maybe it's because I'm older now and have experienced enough health
problems for me to TRULY appreciate the benefits of low-carb that go
well beyond weight loss/control, but it finally DID click with me, so
there's hope for others :-)  This ephiphany, though, much like making
the decision to go on (any) diet in the first place, has to be made
individually in the person's own good time, and no amount of advice from
anyone else will make that happen if the person isn't ready.  In my
case, I think it also has something to do with the fact that I HAVE
learned to accept that I simply CANNOT do everything like "normal"
people and expect to get the same results as those imaginary people.  
Stubbornly insisting to myself that I CAN just ignore physics and wish
and hope for the best just makes things worse and sets me up for
failure.  Accepting and EMBRACING this as a permanent change in my
eating lifestyle has really made ALL the difference in my attitude on
MANY levels.  I don't know that I would EVER have come to that
conclusion, however, if I hadn't tried Atkins and seen and experienced
the dramatic (long term) results for myself and realized how doable it
WOULD be to continue eating this way, having made the decision.  Now I
eat this way because it's what I WANT to do, not because it's what I
HAVE to do.  It's all a matter of perception, baby!