Example:
We were teaching kids, with a swapping rota so each group got two classes from each of the three teachers per day. We had agreed all the topics/activities beforehand in a meeting and made a plan of who taught what per class. As you normally do. It’s not rocket science.
I go into class and start my activity. The kids say “we did this last lesson with Matt”.
I go and find Matt- for some reason he’s in the corridor rather than his class.
Me- Matt, did you teach my activity with group one?
M- Whoah, calm down there, we don’t need to make this like a rigid thing
Me- actually yeah we do need to stick to what was agreed because I just walked in and the kids say you did my class with them rather than the thing you were supposed to teach
M acts like I’m being really unreasonable and then says basically he taught a really half-arsed version of my class, so I have to change everything I had planned on the spot, which is stressful and also means the time I spent planning was wasted.