Seems like people are mostly motivated by looking better, so those progress pics become one of the main reasons they do this. I wish it was health and overall life improvements that motivated people to lose weight, but you can’t really take a picture of having less joint pain or get as many upvotes for playing sports again as a shirtless body pic will get.
I don’t mind progress pics, but I wish the ones that show a lot of the lower waist would be NSFW. I’m really glad you are looking and feeling better, but I don’t want to see more of you than I’d see at a beach.