Why do they pick her over me?

ok so i have a sister that is the same age as me and every one likes her she has blood hair that goes to like the middle of her back and blue eyes no body likes me i have brown hair same lenght and hazel eyes every one is just like you soo ugly why cant you look like your sister if you need a visual look up pictures of rosie huntington whitley (some people say i look like her) and candice ( my sisteer looks like her) why do guys always seem to pick her? and when i do have a boyfriend they only use me to make another girl jealous or so they are not bored and they can go around saying the have a girl friend it is sooo unfair.