When it comes to People Photography the most important things are Expression and Gesture. You are trying to capture the real person in a single image and to do that it is critical that they feel relaxed and comfortable. If somebody is stressed out and taken out of their comfort zone while being photographed then that will impact negatively on the final image.
It is for this reason that I was amazed to come across a Wedding Party having their formal portraits taken on the end of a pier in a busy holiday resort on a blustery afternoon.
The bride and bridesmaids are clearly unhappy with the cold wind blowing the hair that they spent a huge amount of time and money getting done a few hours earlier. Also the large group of people shouting and cheering is doing nothing to make them feel less stressed.
Always have a Plan B and be ready to adapt to the changing circumstances you are presented with.