How does project management processes work with the success of a project?

It is about tailoring the PM processes to the project and integrating them to fulfill the project objectives.

Project Management processes form the crux of the success of any project provided process is coupled with common sense. Process must not be applied in a way that it forms a hindrance to the actual functioning of the project. However, if process is followed, while it may seem as an overhead while the project is on-schedule and within budget, the real advantage of following project management processes can be observed whenever there is an unexpected event that derails the schedule or requires going back to the drawing board. WHile everything is smooth sailing, a project is also well represented in terms of progress by milestones met or expectations made during the early phases. However, I believe the major advantage is that these processes allow for smoother handling of unexpected requirements and events which are unfortunately inevitable in any real-life project scenario

In my point of view, from the budding stage itself project management has a great role in project planning, which is the vital part. Once the planning is examined and revised several times, we get the backbone for project management. 

Then at each stage there is a human or natural factor of obstacles arising. Resolving these too has its major share on the project management processes.