Normal. You'll get used to it. I've shadowed probably 10 or so times and it is getting better.
I would advise that you do spend some time w/ the staff. Sure you're there to see what it is like to be a dentist, but you are also seeing how to run a dental office, and a huge part of a dental office is your staff. Ask them what their job is about, what education and certification they had to have to do what they do, ask them why they became whatever they are, and ask them lots of questions! If it is an office w/ a male doctor and all female staff, ask the females about the male/female barrier, and the doctor/staff barrier. They will give you very important tips on how to keep things smooth. Make the staff feel important too, they will make your shadowing experience much better if you show them you're there to learn about the whole thing not just being a dentist! Letting the staff know how important they are is something I think we will all have to get good at as future dentists if we want to have successful practices.
Plus you should get in good w/ the staff, because if you are at a busy office, they may be the only ones who take the time to explain procedure to you. Plus, surely they will all talk about you at lunch, so best to be on everyones good side, especially if you are going for a recommendation.
Also if they have an office manager incharge of hiring, talk to them and find out what they look for in the people they hire.
There is nothing any person, even the patients, at the office can tell you that won't be valuable in someway.