They're both.
Large breasts -- back problems, assumption that you're not very smart, self-consciousness (because people stare at you all the time).
Large breasts -- control over men
Its like being good looking. You get unwanted attention, but people bend backwards to make friends with you. Seriously, given all things equal being good looking is a very big advantage. Now, whether or not the advantage that offers you is worth it depends on the person.
If any thing that would boost a girls self esteem right?
When people don't look at your face or eyes when you're talking, its very, very damaging to self-esteem. Its as if you're not a person. Try it. Whenever you talk to someone, look at something ELSE other than their face/eyes. You're going to piss them off.