Truly poor leadership. The majority of management across all roles are people who have no life experience outside of Booking (usually in a sales capacity), lack educational credentials you'd expect, etc. In some cases, the leadership teams of entire departments are a group of personal friends with no credentials to have comparable level jobs outside of Booking, but their aligned interest to protect each other and their understanding of ways to manipulate Booking's "data" culture covers their tracks. HR pays lip service to things like this (there is literally a line in our compliance handbook that says managers cannot be involved in hiring or management of personal friends), but nobody actually cares enough to step in and enforce (or even investigate) it.
If you come in as a fresh graduate with no experience, this can work in your favor--you will work on interesting projects quickly and advance quickly (unfortunately to be one of those very inexperienced people in a high level leadership position). If you are a mid-career transfer, Booking is a dead-end unless you simply want to live in Amsterdam (my case, as they took care of relocation, etc.) and fly under the radar until you find something more interesting or decide to go back home.
I can say that a significant proportion of managers/directors are dependent on personal friendships, ability to manipulate data in front of others who are equally incapable of critical analysis, or both. There is nothing more discouraging than being recruited for your experience and running into directors who are less experienced than the people you used to manage but also unwilling to listen because of the positive-reinforcement they have gotten for so long in this unique culture.
When business is good (the Google machine still works to drive business), quite frankly it doesn't really matter--the incompetency and inefficiency throughout management is hidden. If the business environment ever changes (i.e. Google tweaks their business model), chaos will ensue.
