>Look handsome in the mirror >look like shit in video

Because only Chad is immune from suffering in this life.

robot syndrome

Because you're not really giving yourself an objective look when looking in the mirror. Once you separate the person in the mirror from you you will start to really see your flaws.

Because cameras distort the image. Things don't actually look the same in a picture as they do in person.

the mirror is reversed. you develop an image of yourself that is the opposite of what you look like and become accustomed to it, you subconsciously hate other unreversed images of yourself.