Some people don't see their own weight loss. You look at yourself in the mirror everyday and the changes of weight loss happen slow enough that you wouldn't see it. You basically are "blind" to the changes that would be happening because each day when you look, the change was so small that it becomes your new normal and it would take bigger losses before you really feel like you have lost anything.
If you could not look in any mirrors from the time you start until the point you had dropped about 30 lbs then you would likely feel like you see the difference. But if you are looking in the mirror everyday, you can drop 50 lbs and be convinced that nothing had changed. You could also consider taking pictures to help you see the difference. Take one photo at the start and then take a photo every time you drop 20 lbs. Then you will have the photos to compare to help you see the differences.
Also, don't just watch the weight of your body on the scales. Get a measuring tape and keep track of a few key body points to measure. For a man, chest, waist, hips, and thighs would be some key points to track the measurements on. Even when the scale doesn't change too much, you might see some changes with a tape measure too especially if you are exercising to tighten and tone muscles as the fat drops off. Check measurements and body weight about once a week.