I think the thing to keep in mind, as folks who will probably never/rarely experience, about boob jobs is there are many factors that come into play with how they look in the end. Yes location of insertion, augmentation type, filler material, quality of surgeon can all be very important.
But even if everything went perfect with the surgery, the body can still reject it, it is still a foreign agent and that can also impact healing and scarring.
It's a lot like tattoos, aftercare is important, but even if your artist was flawless, your skin just may not be compatible, your healing ability may not be conducive to having clean lines, and your tattoo comes out looking raised, or blurry, or even patchy as your body physically rejects the ink.