Bad feeling about just started sprint

How did your retrospective go? Did this person raise any concerns in the retrospective? In the next retrospective you need to bring this to discussion with the team. I would make sure the value that we deliver as one of the legs (I use spider web in most cases) for the team to raise problems on. This is a very good technique to understand what the team really wants to handle and fix (not just this one person!). using this technique if there are not enough votes (dots on this leg) let the team choose whats most common problem they want to handle first as a team. 

Soon it may be evident that only this one person thinks we are not delivering right value to the customer (Which I believe is the case as the mindset of "if we do this" they will ask for more is not even close to any of the agile manifesto or scrum values). This team member in question does not seem to have trust in the the team, PO and the customers (end users/stakeholders) are you are delivering this product for ! you need to have one on one coaching sessions with this individual especially regarding how the most important factor to measure value delivery is through customer satisfaction. 

https://survicate.com/customer-satisfaction/importance-customer-satisfa…

While it is a good practice to GUIDE them what they really want. This is true in many cases and prototyping and frequent demos (shorter sprints) help the team to engage and guide the customer in the right direction regarding their needs. Many times they will learn about needs and things that they did not even they needed! That is the way an agile team should interact, with the sole purpose f making the customer happy! Not shunning them away from not doing what they want !

Your team member in questions needs to be certified as a PSD and meanwhile you have to explain him what agile really means starting with the 4 principles of the agile manifesto. Also his behavior seems to be detached from the rest of the team and no respect for Scrum the team choose to follow as he is choosing items without respect to all the effort put by the PO and team in ordering them by value !

If the situation does not change after you coach him and if he wants to hijack the next retrospective towards what he wants to discuss without giving respect to what the items the team collectively choose to discuss, as a self-organized development team has all rights to let go of a person who is bringing down the entire team!

At the end of the meeting we didn't had the feeling that we were finished, but we had enough storypoints to fill the sprint with.

Were the team able to agree a Sprint Goal and jointly commit to it?

Is your backlog prioritised by the PO? If yes, then how can a dev go and pick the story midway in the backlog? This move has to be approved by the PO and another scenario I see it to be occuring is only when all the stories above this story are blocked for one reason or another reason or not in a ready state to be played into the sprint.

Hope this gives you enough tool to manage team member expectations in line with backlog prioritisation and still maintain team motivation !!

-Abhi

I am with Ian here. Despite the clouds and storms the development team must achieve a shared commitment to the sprint goal along with a plan. 

All voices must be heard. Behind the negativeness shown by this team member there might be something valuable to the whole sprint planning that, if not expressed somehow, could be totally missed. Did the rest of the team members react objectively to that or were they there as observers? Did they provide their opinions too?  Remember that conflict performed in a constructive manner is usually benefitial in agile and shouldn't be freely avoided. 

Being negative is definitely not a trait welcome by scrum values, however it can be coach and improved. If you as a scrum master detects this as an impediment to the team i.e. for developing a planning to its full potential, I'd say it's your turn to have a word with the person and figure out the underlying reasons for this behavior. Sometimes team members are really influential, have temper, their words could affect others, etc. If that is deemed to be a problem, then act.

and had his own opinion about we should or shouldn't take stories because if we start this, the customer will ask for more

So? That is not a problem, isn't it? The product owner prioritize the backlog according to maximun value. He has the last word on what is up or down the list. Was he convinced by the arguments of the team member? 

I'm not sure if you can fix this sprint but you can learn from it and make sure this does not happen again. The development team should be involved in the product discovery process as early as possible. Joint application development session (JAD) is a good opportunity for stakeholders, product owner and developers to discuss new features. Product backlog refinement meeting is another good opportunity for developers and PO to talk about new user stories, their priorities and get consensus on them before the next sprint.

If this team member doesn't change his/her attitude, then you, as a Scrum master, need to provide more Scrum training and discuss this issue at the sprint retrospective.