Society's images/ideals. To the "average" person, they can always find something wrong with themselves when they look to what society says is right. Most don't know this, but, I've always (sometimes still do) struggled with what I look like. My pediatrician actually warned my mom to watch what I ate when I was younger because I had the potential to gain weight easily, putting me at a higher chance of coming overweight/obese. I remember my mom telling me that when I was younger I once told her, while sitting somewhere, that I didn't like that my thighs touched when I sat down. She then told me that she was worried because between what the doctor had told her and what I had told her, it sounded like I could be at risk for developing some type of eating disorder- thankfully I didn't.
Being a dancer(along with becoming a dance major) definitely could have put me on a path that lead to an eating disorder, thankfully, I go to an amazing studio and now university that embraces all body types and doesn't have a "body norm" that you have to fit into. Embrace who you are and how you look, it will be one of the most amazing feelings in the world. Don't be afraid to go out and do/try different activities because of what people might say. It doesn't matter what others/our society thinks of you, if you enjoy doing it, then do it. Don't be afraid to live.
No one in this world has a perfect life, body etc... they've just come to realize that it doesn't pay to hate what they look like, what they are going through because it's not going to be the same forever. Stop believing that you have to constantly have to have make-up on, pin-straight hair, perfect beautiful whitened teeth to be beautiful (of course there is ABSOLUTELY nothing wrong with having these things). Stop believing that there is only one body type and if you don't have it then too bad...there are multiple body types. Just stop.
You aren't going to be able to live up to society's images of the "Ideal __________" fill in the blank, you just aren't. There is always going to be some one who you think is smarter, prettier, stronger, better- there just is. And what the world deems "perfect" one day can always change, it might not be the next day or week, but eventually it'll change and guess what....you'll be back to square one.
I still struggle sometimes with what I look like, but it's getting easier and easier to love myself and I hope that it does for you too because it will and it's going to take time, but it will happen and don't be afraid to let it!
"Today you are you, that is truer than true. There is no one alive who is youer than you" - Dr. Seuss