The need for a sprint objective

I know, all the knowers and doers know it: if you're going to do agile: you better have a sprint objective! For you not-knowers: a sprint objective is a sentence which describes what you want to accomplish during the sprint. We've been not so good at this. That is: I've known the objective, but no one else has. Not the product owner, not the scrum master, not the development team.

So, what happens if you don´t have a sprint objective:
- The wrong things get done
- I get disappointed
- The product owner doesn't know what the delivery contained.

This sprint, we had a storyboard and I had a clear sprint objective. We also had some side projects, some POC:s (Proof of concepts) which we wanted tested. Small stuff. The problem was that it was fun stuff. So, people took those tasks and thought that someone else would pick the other stuff. Or waited on someone else to start. Or something. So, the last week of the sprint and no where near the objective. So, I pointed that out:
- Hey, I see that we don't have X! Someone responded:
- Then we have to cut it.
- But X was the objective.
- But we've completed Y.
- Completed?
- Yes, you can do Y in the actual application.
- But Y was only going to be a POC.
- But we were so close so we went the whole way.
- O.H. M.Y G.O.D....

So, next sprint I'm going to print the sprint objective in large letters and hang it over the most used white board, the one we use for scrum meetings. No one is going to miss the sprint objective of September. I just have to make the product owner set one....