I was curious. If someone with larger breasts were to get too small implants, what would happen?
You really cannot get "implants too small" for most women, but will just have a smaller breast. Going up one cup instead of two is not a problem if that is what is desired. The problem is when women get implants too large for their breasts. The tissue is stretched and thinned and cannot support the weight. Initially, the women may have hard balls on their chest. Most ladies with large breasts should not get large implants.
If you naturally have larger breasts and you decide to go for smaller implants you should be prepared to see a very subtle change in the long run postop. It is all about expectations and aesthetic goals