Having read all these responses, I would like to add my own two cents worth. I travel extensively because of my career. I have spent months on end going to the same place or flying as little as once a month. I have been doing this for a little over 15 years. I have seen all the changes since 9/11 and I agree with most of them.
Six years ago I had a titanium knee replacement. Since then I have been patted down or if possible, go through the backscatter machine. Now, in saying this I have found that before I go through the regular magnometer (screening machine) I indicate that they will have to call for a "female assist". The reason I bring this up is because even though I have not gone through any surgery, because of my size, hair stlye (spiky brush cut), voice and attitude I come off as male. All of the female TSA agents have treated me with respect . They explain everything they are going to do and will ask if you prefer a private screening. I treat the pat downs with a bit of humor by engaging with them by saying things like "you know you have to buy me dinner now" or "you know we have to stop meeting this way" but I always say it with a smile of my face! Most of the TSA agents in Tucson, AZ know me by face now and will have someone ready to gather up my belongings and escort me to a screening area. I have never missed a flight because of this process, nor have I been separated from my belongings. I am always able to see my belongings during a pat down. I actually missed packing up my laptop on my return home once but TSA contacted me that night (I have a business card taped to the cover of my laptop). When I went to retrieve it, all I ahd to do to prove that it was mine was start it up and enter the correct password (and show ID).
I do have one funny story......Recently I came through security in Frankfurt, Germany - not TSA but German officials. Of course, the magnometer buzzed when I went through and there were a male and female standing there with the handheld devices. I looked at the male and he was ready to start patting me down....I then looked at the female and said in my broken German "Ich eine frau"....I am a woman! He immediately stopped and her eyes got real big as she apologized profusely!!
Oh, and by the way....if you want to bring back cheese from Wisconsin home to your friends or family.....Be aware that it is the same consistency as C4 explosives. They will pull your carry on bag and ask to look inside! I spent a whole year going back and forth from Tucson to Milwaukee....I call that my "cheese smuggling trips"!
Relax and listen to the rules and there shouldn't be a problem.....