Once in awhile I've thought I'd like to be a little bigger; I've been an A my whole life, but recently was fitted and wear a B at times, but now that I have found the right bras, I could care less. I can't imagine having breasts large enough that they interfere with daily activities.
I once was at a luncheon/conference for a charity group I belong to. This was many years ago. The speaker was a plastic surgeon who was talking about breast enlargement and he was showing us implants (the actual thing that goes in your body). Someone started throwing the thing around and it landed squarely in my lap. I was mortified and decided I would would rather wear a padded bra. Of course, at that time I weighed about 92 pounds, so I really was small up top.