I completely agree with previous comments but I just want to talk about the most important WBS problem and how to fix it. Sometimes teams get caught up in the discussions and end up trying to sequence the work. People add arrows to the WBS, or start to map out the order of tasks on a different sheet, or in a note-taking tool, or even writing dates on the sticky notes as you put them up on the wall. This is a hard one because ultimately the WBS is an input to your project schedule. You will be using it to help you with sequencing tasks… just not right now, so to fix this problem we as a project manager should not let teams talk about task sequencing. This is a facilitation issue. Be strict on the purpose of the session and park any discussions about the order of work.