GUYS: Why are some of you soo shallow?

Why do some of you guys (not all) only go for the slut with big , honestly. You go for the ugly slut that is 'easy' for you to 'score' with -___- why cant you see girls for how beautiful inside and out and not their size...? I know not all guys are like this but i am particularly talking about boys my age that i go to school with they are 14 - 15 year olds...is it their hormones? like is all they think about seriously so their eyes wander (and not subtly) to our ? i want opinions for guys of all ages and be honest please! :) x