When they give the woman back problems, they can be.
when you need a wheelbarrow to haul them around, they're getting close
As long as they are natural they can never be to big.
Absolutely! I personally don't like big ones. I prefer a handful, no more.
Definitely, there has to be some overall proportion involved.
Yes. I, personally, have traveled to the edges of sanity in that department. It is not for the faint-hearted.
her areolas can be.
No, that's probably not possible. Even girls with very severe gigantomastia are proportionatly more sexy than girls who "only" have huge ****.
Yes, they can be too big...to the point of being too heavy for the back to support without strain. Some women get breast reduction surgery for that reason.