Health and fitness are, in my experience, more about the changes that you make to your lifestyle than the number on the scale. If you put the honest effort in, the results will come.
If you hit a bump in the road, let's say your weight starts to go up or your rate of loss slows down, then you just have to step back and re-evaluate! I feel like this part is what most people are missing. It's easy to get discouraged and just want to quit