I'm still in Japan and I went out to a famous Buddhist town of Nikko over the weekend. Back in 782 CE, Shodo Shonin established a monestary here. There are lots of Shinto shrines and Buddhist temples in the area. I took a hike up to one shrine up a small 900 meter high mountain that was marked on my map.
The map couldn't prepare me for the hike. Sure, it showed I would be going up, but it didn't show the step switchbacks I would have to cover to get to the top. It also didn't give me any idea of what the shrine at the top of the mountain would be like. However, I was glad I made the journey.
A project plan is like a map. It's meant to help guide us, but that's it. It's not the project or our deliverables, it's just helps us get there. While the best project plan doesn't necessarily mean we'll make the customer happy, without a plan we run a high risk of getting lost. So make sure your plan will get you to were you want to go.