Put up two posters labeled 'proud' and 'sorry'. Team members write down one instance per sticky note. When the time is up have everyone read out their note and post it to the appropriate poster. Start a short conversation e.g. by asking:
Did anything surprise you?
What patterns do you see? What do they mean for you as a team?
Find the source of problems whose origins are hard to pinpoint and lead to endless discussion Source:
Write the problem you want to explore on a sticky note and put it in the middle of a whiteboard. Find out why that is a problem by repeatedly asking 'So what?'. Find out the root causes by repeatedly asking 'Why (does this happen)?' Document your findings by writing more stickies and showing causal relations with arrows. Each sticky can have more than one reason and more than one consequence Vicious circles are usually good starting points for actions. If you can break their bad influence, you can gain a lot.
If your team has a tendency to see obstacles outside of their team and influence and primarily wants others to change, you can try this activity:
Draw a big rectangle on the board and another rectangle inside of it, like a picture frame. Hang all complaints and grievances that surfaced in previous phases into the frame.
Now comes the interesting twist: Explain that if they want anything in the outside frame to change, they will have to do something themselves to affect that change. Ask the team to come up with actions they can do. Put these actions into the inner rectangle (near the outer sticky they are addressing).
Let team members appreciate each other and end positively Source:
Agile Retrospectives who took it from 'The Satir Model: Family Therapy and Beyond'
Start by giving a sincere appreciation of one of the participants. It can be anything they contributed: help to the team or you, a solved problem, ...Then invite others and wait for someone to work up the nerve. Close, when no one has talked for a minute.