In an ideal world, things would always go to plan – but since we don’t live in an ideal world, they don’t; hence why the best-laid plans of project managers often go awry.
More often than not, detailed plans laid out on neat charts projecting months (even years) into the future, tend to describe a fictional reality; and perfect plans tend to describe fictional realities perfectly. Because no mattermuch time, effort and care goes into planning sooner or later, some s likely to deviate from the plan
That’s not to say we shouldn’t plan – we should.
But instead of trying to create a ‘perfect plan’ in detail upfront, it’s better to start with a plausible plan and refine that plan throughout the lifetime of the project; because when you refine your plans to reflect reality (rather than trying to get reality to reflect your plans), you’re more likely to achieve your project objectives.