M&A integration playbooks are built from the lessons of prior deals, and most firms treat their playbook as something close to a script — follow the steps in order, adapt lightly for context, and the integration proceeds predictably. In my experience, playbooks that get treated this way consistently underperform against the specific politics of the deal actually in front of them.
Every deal has its own unwritten history — grievances between the two organisations' leaders, informal alliances, unresolved questions from the negotiation that everyone quietly remembers even though they're not in any document. A playbook, by design, can't capture any of this, because it's built from the generalisable lessons of prior deals, not the specific texture of this one.
The integrations that work best treat the playbook as a starting draft, explicitly revised in the first two weeks based on a genuine mapping of this deal's specific politics — who has informal influence beyond their formal title, which prior grievances are likely to surface as integration decisions get made, where the real resistance will come from.
This mapping work is uncomfortable, because it means explicitly acknowledging organisational politics that nobody wants to name in a formal integration document. But integrations that skip it tend to discover the same politics anyway, later, in the form of decisions that mysteriously stall or resistance that seems to come from nowhere.
Cultural integration isn't a workstream separate from the 'real' integration work. It's the whole deal, playing out at a smaller scale in every specific decision — and a playbook that doesn't account for it is a playbook that will need rewriting mid-deal regardless of how well it was built.