Effectiveness of the pre-production process

The planning of the sequence has tought me a lot about film-making,
for example that you have to be flexible
(our group changed our idea all the time even on the shooting day) and can't stick to one idea all the time.
I also learned that planning is very necessary and that this is a lot of work.
We struggled at first with deciding on a final idea, but in general we worked well as a group.