It is very, very unusual, in my experience for someone to not like their breast augmentation. I think the most common reason people may have slight regrets is that it is early on in the healing and settling phase and the patient does not realize that with time the appearance will become much more natural.
It is important to remember that the post-operative swelling will actually get worse for 3 days. Also, the swelling will not be even. You will swell disproportionately in the upper pole, making it look like they were placed too high. I remind my patients frequently, that you need to allow 3 months for them to drop into the correct position.
Another reason for possible early dissatisfaction is that the implants can feel very firm. I use the analogy, it is like getting 9 months pregnant in one hour. It takes time for the soft tissue in your breasts and the overlying muscle to stretch and soften. They will get softer and more natural for over a year, so once again, it is important to be patient.
Sometimes, after surgery, gravity will cause the nipple-areolar complex to sag with time. This is not too difficult to correct and usually can be fixed in the office under local anesthetic. I sit you up at the time of surgery and make sure that the nipple is properly positioned. However, if the elasticity of your tissues is not very good, it can descend in the weeks after surgery. Remember, it is relatively easy to raise the nipple position, but next to impossible to lower it. Thus, if I am not sure a nipple elevation (mastopexy) is required, it is much better to allow a few months to elapse to see how the breast settles with time.
There is always an asymmetry between the breasts. Sometimes, I can make them somewhat more similar but I rarely can make them exact. Also, realize that I will sometimes put in different size implants to even up the volume, but sometimes the actual shape between each breast is different. This will lead to there being some asymmetry between the breasts. It is very rare for a woman to have exactly identical breasts. Sometimes after surgery, a patient will be much more critical of each breast and will notice differences that she failed to notice pre-operatively.
There are certain “tricks” and “skills” a good plastic surgeon can utilize. However, doing a BA is not the same as doing sculpting or working with clay and there are some limitations of what can be achieved. As I tell all my patients, your expectations of cosmetic surgery must be realistic. After a breast augmentation, just as in life, it is best to aim for good and be satisfied, rather than aim for perfection and be assured of almost certain disappointment.