After attending really many retrospectives, meetings related to lean initiatives, process improvements, etc, etc. I developed an observation I want to share with you. This is an anti-pattern.
On many of these occasions, after asking the participants to put their thoughts on sticky notes (and it can be about anything, problems, ideas, improvements, etc.) the meeting facilitator says: OK, so now that we have read all the sticky notes, I guess maybe let's group similar ones together.
This is exactly the moment when I say to myself (and this is also my advice to you): run away from that meeting!