I think collaborative skills and mindset are very important when it comes to both building the important relationship with the target as well as within the DD team. An acquisition including PMI is a fairly lengthy process so having a collaborative long-term intent in the first place is important. The two most important collaborative skills are probably listening skills to understand the needs and interests of the other party and to avoid becoming defensive when things are not going according to plan. Not only will the problem solving ability go down when becoming defensive, but it will also put other people in the red zone. Creating a safe environment so that people chose to be open about problems they identify or things they do not understand is also an important collaborative skill.