Ok, so here is my story:
I had my appointment in the morning (8:40am), however, I was actually called at 10:15am!! Believe me when I tell you, the interview only took 10 minutes or less! The officer went straight to point to verify all the information on the N-400. Before starting I had to swear to tell the truth, then she asked for green card, passport and DL. That was it! I had a loads of documents with me and she didn't ask for any of it. She asked me about taxes (if I filed or owe) and I said yes and no, respectively. She asked about criminal history, terrorist activity, and member of communist party and I replied no to all. She asked if "I loved the USA"..haha..I thought this question was funny. I answered "Yep, I sure do". She asked me if I used any other name..Pretty much we went over the N-400 line by line.
Then she asked me to read "Where is the Whitehouse?" and I had to write the answer "The Whitehouse is in Washington D.C." Then she gave me the civics test, I only remember these questions: Who vetoes bills? What is the capital of NJ? Who did we fight in WWII? What is the law of the land? I answered all correctly and that was it! No contention, no problems, VERY fast and painless! I had oath 2 hrs later and I was out of the there.
The process is very simple, don't stress over it, especially if your application is straightforward and you have nothing to hide. All the best to you all and God Bless the Good ole USofA.