I know for me personally, when I got to a point where I wasn't seeing results, I would just quit trying and go back to my old unhealthy habits. Which typically meant I would gain back any weight I had lost, and then plus some.
Something I try to keep in mind is not letting one specific thing be my focus. I know we can tend to allow the scale to determine how well we are progressing; but we can't let that be the only factor. I had a friend yesterday tell me she had only lost a pound, but was losing inches. So, just because the scale didn't go down much, she's making some type of progress in the fact she's losing inches.
Another personal example, that I'll never forget when I don't see my weight going down, of why it's important to not let the scale determine your progress is when I lost only five pounds in two months between my assessments. If weighing was the only factor to my assessments, I wouldn't have seen the improvement between my lean mass and fat mass. The scale only showed I lost five pounds, but what it didn't show was that I gained 13 pounds of lean mass and lost 18 pounds of fat mass.
I still have moments, in what I call my health and fitness journey, where my progress is not only slow but sometimes no progress at all. I've even had moments in my journey where I've gained weight and didn't improve at all between my assessments. But, the difference between my mindset from the past and today, is when I have these "slow progress" moments, I don't give up on myself. Don't get me wrong, I definitely get frustrated, but I don't get discouraged and quit!