Susan,
Keep in mind that many people who say things totally outlandlish like your boss are just a bit self-conscious themselves and don't know what to say. In their own way they are thinking they are helping put you at ease because they feel like they have to say something. Even the waitress was probably fishing for information from you because she could sense the wisdom you project and wanted to help her sister but didn't know what to do.
I don't see any religious reference in any of your posts but I do want to share my beliefs with you. I strongly believe that God puts us in situations often that allow us to take our experiences and help others. For example, you have shared a situation that has angered you and made you feel self-conscious but all of us here are staring at your post with our jaws hanging to the floor marveling that you have been a cancer survivor for THIRTY-FOUR years!!
Hold your head high, believe in yourself and remember nobody really needs a response from you. Now, if you look at it like you are really helping them through some of their stuff...the limits are endless.
I am honored to meet you, by the way and Happy Birthday next Tuesday.
Ed