Anybody here have experience in the patenting department?

What is patentable? What is not? I mean in a patentable process is everything patented (the way things work, the look and feel...) or should different patents be applied to different aspects of what needs to be patented?

Is it worth it to patent or is this only reserved to the big corporations because they're the only one to have the financial resources to fight for their rights?

What are the positive and negative sides to such a process?

Thank you for additional feedback on things I could've forgotten.