Good topic. A few thoughts.
I think sometimes the loss of motivation can stem from feeling deprived. There are basically
two ways to cure that feeling: 1) throw your cash around and buy more shit, or 2) cure the source (
kill the desire). Approach #2 is where I am getting the
best motivation, because it's a long-term solution! If I choose #1, that money is spent and gone, and at the beginning of the next month I'm back to square 1...poorer and no better off. Plus, I've just fired all my little cash employees, which can no longer reproduce and make me some more baby cash.
It's a mental adjustment. It's realizing - hey, I actually don't need to go out to eat "for the experience" more than once or twice a month. I don't feel like I'm giving anything up and it's an easier path to sustain. Also see MMM's article which talks a bit about controlling desire:
http://www.mrmoneymustache.com/2012/09/18/is-it-convenient-would-i-enjoy-it-wrong-question/It's similar when I'm working on weight loss, I guess. Sometimes the end goal itself is NOT tantalizing enough to stay on track and you think, what's the point? But when it becomes about the journey...about living a healthier lifestyle, or a less consumerist/wasteful lifestyle, or a more mindful lifestyle....etcetc....THEN each day feels like an opportunity and not a sacrifice.
Keep in mind that most people are going to choose approach #1. There's something very freeing about approach #2, and on top of that, it speeds the path to actual freedom (FIRE) by just needing less from life (that can be bought, anyway).